diff --git a/browser/devtools/inspector/test/browser_inspector_bug_952294_tooltips_dimensions.js b/browser/devtools/inspector/test/browser_inspector_bug_952294_tooltips_dimensions.js
index ffdea9ab0d3..2016213ce94 100644
--- a/browser/devtools/inspector/test/browser_inspector_bug_952294_tooltips_dimensions.js
+++ b/browser/devtools/inspector/test/browser_inspector_bug_952294_tooltips_dimensions.js
@@ -75,12 +75,14 @@ function selectDiv() {
 }
 
 function testTransformDimension() {
-  let deferred = promise.defer();
-  info("Testing css transform tooltip dimensions");
+  return Task.spawn(function*() {
+    let tooltip = ruleView.previewTooltip;
+    let panel = tooltip.panel;
 
-  let {valueSpan} = getRuleViewProperty("transform");
-  showTooltipOn(ruleView.previewTooltip, valueSpan, () => {
-    let panel = ruleView.previewTooltip.panel;
+    info("Testing css transform tooltip dimensions");
+    let {valueSpan} = getRuleViewProperty("transform");
+
+    yield assertTooltipShownOn(tooltip, valueSpan);
 
     // Let's not test for a specific size, but instead let's make sure it's at
     // least as big as the preview canvas
@@ -92,22 +94,23 @@ function testTransformDimension() {
     ok(panelRect.width >= w, "The panel is wide enough to show the canvas");
     ok(panelRect.height >= h, "The panel is high enough to show the canvas");
 
-    ruleView.previewTooltip.hide();
-    deferred.resolve();
+    let onHidden = tooltip.once("hidden");
+    tooltip.hide();
+    yield onHidden;
   });
-
-  return deferred.promise;
 }
 
 function testImageDimension() {
-  let deferred = promise.defer();
-  info("Testing background-image tooltip dimensions");
+  return Task.spawn(function*() {
+    info("Testing background-image tooltip dimensions");
 
-  let {valueSpan} = getRuleViewProperty("background");
-  let uriSpan = valueSpan.querySelector(".theme-link");
+    let tooltip = ruleView.previewTooltip;
+    let panel = tooltip.panel;
 
-  showTooltipOn(ruleView.previewTooltip, uriSpan, () => {
-    let panel = ruleView.previewTooltip.panel;
+    let {valueSpan} = getRuleViewProperty("background");
+    let uriSpan = valueSpan.querySelector(".theme-link");
+
+    yield assertTooltipShownOn(tooltip, uriSpan);
 
     // Let's not test for a specific size, but instead let's make sure it's at
     // least as big as the image
@@ -119,22 +122,24 @@ function testImageDimension() {
     ok(panelRect.height >= imageRect.height,
       "The panel is high enough to show the image");
 
-    ruleView.previewTooltip.hide();
-    deferred.resolve();
+    let onHidden = tooltip.once("hidden");
+    tooltip.hide();
+    yield onHidden;
   });
-
-  return deferred.promise;
 }
 
 function testPickerDimension() {
-  let deferred = promise.defer();
-  info("Testing color-picker tooltip dimensions");
+  return Task.spawn(function*() {
+    info("Testing color-picker tooltip dimensions");
 
-  let {valueSpan} = getRuleViewProperty("background");
-  let swatch = valueSpan.querySelector(".ruleview-colorswatch");
-  let cPicker = ruleView.colorPicker;
+    let {valueSpan} = getRuleViewProperty("background");
+    let swatch = valueSpan.querySelector(".ruleview-colorswatch");
+    let cPicker = ruleView.colorPicker;
+
+    let onShown = cPicker.tooltip.once("shown");
+    swatch.click();
+    yield onShown;
 
-  cPicker.tooltip.once("shown", () => {
     // The colorpicker spectrum's iframe has a fixed width height, so let's
     // make sure the tooltip is at least as big as that
     let w = cPicker.tooltip.panel.querySelector("iframe").width;
@@ -144,21 +149,43 @@ function testPickerDimension() {
     ok(panelRect.width >= w, "The panel is wide enough to show the picker");
     ok(panelRect.height >= h, "The panel is high enough to show the picker");
 
+    let onHidden = cPicker.tooltip.once("hidden");
     cPicker.hide();
-    deferred.resolve();
+    yield onHidden;
   });
-  swatch.click();
-
-  return deferred.promise;
 }
 
-function showTooltipOn(tooltip, element, cb) {
-  // If there is indeed a show-on-hover on element, the xul panel will be shown
-  tooltip.panel.addEventListener("popupshown", function shown() {
-    tooltip.panel.removeEventListener("popupshown", shown, true);
-    cb();
-  }, true);
-  tooltip._showOnHover(element);
+/**
+ * @return a promise that resolves when the tooltip is shown
+ */
+function assertTooltipShownOn(tooltip, element) {
+  return Task.spawn(function*() {
+    let isTarget = yield isHoverTooltipTarget(tooltip, element);
+    ok(isTarget, "The element is a tooltip target and content has been inserted");
+
+    info("Showing the tooltip now that content has been inserted by isValidHoverTarget");
+    let onShown = tooltip.once("shown");
+    tooltip.show();
+    yield onShown;
+  });
+}
+
+/**
+ * Given a tooltip object instance (see Tooltip.js), checks if it is set to
+ * toggle and hover and if so, checks if the given target is a valid hover target.
+ * This won't actually show the tooltip (the less we interact with XUL panels
+ * during test runs, the better).
+ * @return a promise that resolves when the answer is known. Also, this will
+ * delete to a function in the rule-view which will insert content into the
+ * tooltip
+ */
+function isHoverTooltipTarget(tooltip, target) {
+  if (!tooltip._basedNode || !tooltip.panel) {
+    return promise.reject(new Error("The tooltip passed isn't set to toggle on hover or is not a tooltip"));
+  }
+  // The tooltip delegates to a user defined cb that inserts content in the tooltip
+  // when calling isValidHoverTarget
+  return tooltip.isValidHoverTarget(target);
 }
 
 function getRuleViewProperty(name) {
diff --git a/browser/devtools/markupview/markup-view.js b/browser/devtools/markupview/markup-view.js
index f990eb1edc3..28365ac13c4 100644
--- a/browser/devtools/markupview/markup-view.js
+++ b/browser/devtools/markupview/markup-view.js
@@ -110,7 +110,7 @@ MarkupView.prototype = {
   _initTooltips: function() {
     this.tooltip = new Tooltip(this._inspector.panelDoc);
     this.tooltip.startTogglingOnHover(this._elt,
-      this._buildTooltipContent.bind(this));
+      this._isImagePreviewTarget.bind(this));
   },
 
   _initHighlighter: function() {
@@ -232,7 +232,15 @@ MarkupView.prototype = {
     updateChildren(documentElement);
   },
 
-  _buildTooltipContent: function(target) {
+  /**
+   * Executed when the mouse hovers over a target in the markup-view and is used
+   * to decide whether this target should be used to display an image preview
+   * tooltip.
+   * Delegates the actual decision to the corresponding MarkupContainer instance
+   * if one is found.
+   * @return the promise returned by MarkupContainer._isImagePreviewTarget
+   */
+  _isImagePreviewTarget: function(target) {
     // From the target passed here, let's find the parent MarkupContainer
     // and ask it if the tooltip should be shown
     let parent = target, container;
@@ -247,7 +255,7 @@ MarkupView.prototype = {
     if (container) {
       // With the newly found container, delegate the tooltip content creation
       // and decision to show or not the tooltip
-      return container._buildTooltipContent(target, this.tooltip);
+      return container._isImagePreviewTarget(target, this.tooltip);
     }
   },
 
@@ -1265,6 +1273,13 @@ MarkupContainer.prototype = {
     }
   },
 
+  /**
+   * If the node is an image or canvas (@see isPreviewable), then get the
+   * image data uri from the server so that it can then later be previewed in
+   * a tooltip if needed.
+   * Stores a promise in this.tooltipData.data that resolves when the data has
+   * been retrieved
+   */
   _prepareImagePreview: function() {
     if (this.isPreviewable()) {
       // Get the image data for later so that when the user actually hovers over
@@ -1291,6 +1306,27 @@ MarkupContainer.prototype = {
     }
   },
 
+  /**
+   * Executed by MarkupView._isImagePreviewTarget which is itself called when the
+   * mouse hovers over a target in the markup-view.
+   * Checks if the target is indeed something we want to have an image tooltip
+   * preview over and, if so, inserts content into the tooltip.
+   * @return a promise that resolves when the content has been inserted or
+   * rejects if no preview is required. This promise is then used by Tooltip.js
+   * to decide if/when to show the tooltip
+   */
+  _isImagePreviewTarget: function(target, tooltip) {
+    if (!this.tooltipData || this.tooltipData.target !== target) {
+      return promise.reject();
+    }
+
+    return this.tooltipData.data.then(({data, size}) => {
+      tooltip.setImageContent(data, size);
+    }, () => {
+      tooltip.setBrokenImageContent();
+    });
+  },
+
   copyImageDataUri: function() {
     // We need to send again a request to gettooltipData even if one was sent for
     // the tooltip, because we want the full-size image
@@ -1301,17 +1337,6 @@ MarkupContainer.prototype = {
     });
   },
 
-  _buildTooltipContent: function(target, tooltip) {
-    if (this.tooltipData && target === this.tooltipData.target) {
-      this.tooltipData.data.then(({data, size}) => {
-        tooltip.setImageContent(data, size);
-      }, () => {
-        tooltip.setBrokenImageContent();
-      });
-      return true;
-    }
-  },
-
   /**
    * True if the current node has children.  The MarkupView
    * will set this attribute for the MarkupContainer.
diff --git a/browser/devtools/markupview/test/browser_inspector_markup_765105_tooltip.js b/browser/devtools/markupview/test/browser_inspector_markup_765105_tooltip.js
index 5c5487c89d3..ee13158fd1c 100644
--- a/browser/devtools/markupview/test/browser_inspector_markup_765105_tooltip.js
+++ b/browser/devtools/markupview/test/browser_inspector_markup_765105_tooltip.js
@@ -88,7 +88,7 @@ function testImageTooltip(index) {
     target = container.editor.getAttributeElement("src");
   }
 
-  assertTooltipShownOn(target, () => {
+  assertTooltipShownOn(target).then(() => {
     let images = markup.tooltip.panel.getElementsByTagName("image");
     is(images.length, 1,
       "Tooltip for [" + TEST_NODES[index].selector + "] contains an image");
@@ -97,7 +97,6 @@ function testImageTooltip(index) {
     is(label.textContent, TEST_NODES[index].size,
       "Tooltip label for [" + TEST_NODES[index].selector + "] displays the right image size")
 
-    markup.tooltip.hide();
     testImageTooltip(index + 1);
   });
 }
@@ -117,22 +116,10 @@ function compareImageData(img, imgData) {
 }
 
 function assertTooltipShownOn(element, cb) {
-  // If there is indeed a show-on-hover on element, the xul panel will be shown
-  markup.tooltip.panel.addEventListener("popupshown", function shown() {
-    markup.tooltip.panel.removeEventListener("popupshown", shown, true);
+  return Task.spawn(function*() {
+    info("Is the element a valid hover target");
 
-    // Poll until the image gets loaded in the tooltip. This is required because
-    // markup containers only load images in their associated tooltips when
-    // the image data comes back from the server. However, this test is executed
-    // synchronously as soon as "inspector-updated" is fired, which is before
-    // the data for images is known.
-    let hasImage = () => markup.tooltip.panel.getElementsByTagName("image").length;
-    let poll = setInterval(() => {
-      if (hasImage()) {
-        clearInterval(poll);
-        cb();
-      }
-    }, 200);
-  }, true);
-  markup.tooltip._showOnHover(element);
+    let isValid = yield markup.tooltip.isValidHoverTarget(element);
+    ok(isValid, "The element is a valid hover target for the image tooltip");
+  });
 }
diff --git a/browser/devtools/netmonitor/test/browser_net_image-tooltip.js b/browser/devtools/netmonitor/test/browser_net_image-tooltip.js
index 0da42590f3d..996b95064d1 100644
--- a/browser/devtools/netmonitor/test/browser_net_image-tooltip.js
+++ b/browser/devtools/netmonitor/test/browser_net_image-tooltip.js
@@ -59,16 +59,17 @@ function test() {
       });
     }
 
-    function showTooltipOn(aTooltip, aTarget) {
-      let deferred = promise.defer();
-
-      aTooltip.panel.addEventListener("popupshown", function onEvent() {
-        aTooltip.panel.removeEventListener("popupshown", onEvent, true);
-        deferred.resolve(aTooltip);
-      }, true);
-
-      aTooltip._showOnHover(aTarget);
-      return deferred.promise;
+    /**
+     * @return a promise that resolves when the tooltip is shown
+     */
+    function showTooltipOn(tooltip, element) {
+      return Task.spawn(function*() {
+        let isTarget = yield tooltip.isValidHoverTarget(element);
+        let onShown = tooltip.once("shown");
+        tooltip.show();
+        yield onShown;
+        return tooltip;
+      });
     }
 
     aDebuggee.performRequests();
diff --git a/browser/devtools/shared/widgets/Tooltip.js b/browser/devtools/shared/widgets/Tooltip.js
index 81dd22f4814..9ff91f2fae7 100644
--- a/browser/devtools/shared/widgets/Tooltip.js
+++ b/browser/devtools/shared/widgets/Tooltip.js
@@ -392,19 +392,34 @@ Tooltip.prototype = {
       this.hide();
       this._lastHovered = event.target;
       setNamedTimeout(this.uid, this._showDelay, () => {
-        this._showOnHover(event.target);
+        this.isValidHoverTarget(event.target).then(target => {
+          this.show(target);
+        });
       });
     }
   },
 
-  _showOnHover: function(target) {
+  /**
+   * Is the given target DOMNode a valid node for toggling the tooltip on hover.
+   * This delegates to the user-defined _targetNodeCb callback.
+   * @return a promise that resolves or rejects depending if the tooltip should
+   * be shown or not. If it resolves, it does to the actual anchor to be used
+   */
+  isValidHoverTarget: function(target) {
+    // Execute the user-defined callback which should return either true/false
+    // or a promise that resolves or rejects
     let res = this._targetNodeCb(target, this);
-    let show = arg => this.show(arg instanceof Ci.nsIDOMNode ? arg : target);
 
+    // The callback can additionally return a DOMNode to replace the anchor of
+    // the tooltip when shown
     if (res && res.then) {
-      res.then(show);
-    } else if (res) {
-      show(res);
+      return res.then(arg => {
+        return arg instanceof Ci.nsIDOMNode ? arg : target;
+      }, () => {
+        return false;
+      });
+    } else {
+      return res ? promise.resolve(res) : promise.reject(false);
     }
   },
 
@@ -620,42 +635,44 @@ Tooltip.prototype = {
    *        a number here
    */
   setImageContent: function(imageUrl, options={}) {
-    if (imageUrl) {
-      // Main container
-      let vbox = this.doc.createElement("vbox");
-      vbox.setAttribute("align", "center");
-
-      // Display the image
-      let image = this.doc.createElement("image");
-      image.setAttribute("src", imageUrl);
-      if (options.maxDim) {
-        image.style.maxWidth = options.maxDim + "px";
-        image.style.maxHeight = options.maxDim + "px";
-      }
-      vbox.appendChild(image);
-
-      // Dimension label
-      let label = this.doc.createElement("label");
-      label.classList.add("devtools-tooltip-caption");
-      label.classList.add("theme-comment");
-      if (options.naturalWidth && options.naturalHeight) {
-        label.textContent = this._getImageDimensionLabel(options.naturalWidth,
-          options.naturalHeight);
-      } else {
-        // If no dimensions were provided, load the image to get them
-        label.textContent = l10n.strings.GetStringFromName("previewTooltip.image.brokenImage");
-        let imgObj = new this.doc.defaultView.Image();
-        imgObj.src = imageUrl;
-        imgObj.onload = () => {
-          imgObj.onload = null;
-          label.textContent = this._getImageDimensionLabel(imgObj.naturalWidth,
-            imgObj.naturalHeight);
-        }
-      }
-      vbox.appendChild(label);
-
-      this.content = vbox;
+    if (!imageUrl) {
+      return;
     }
+
+    // Main container
+    let vbox = this.doc.createElement("vbox");
+    vbox.setAttribute("align", "center");
+
+    // Display the image
+    let image = this.doc.createElement("image");
+    image.setAttribute("src", imageUrl);
+    if (options.maxDim) {
+      image.style.maxWidth = options.maxDim + "px";
+      image.style.maxHeight = options.maxDim + "px";
+    }
+    vbox.appendChild(image);
+
+    // Dimension label
+    let label = this.doc.createElement("label");
+    label.classList.add("devtools-tooltip-caption");
+    label.classList.add("theme-comment");
+    if (options.naturalWidth && options.naturalHeight) {
+      label.textContent = this._getImageDimensionLabel(options.naturalWidth,
+        options.naturalHeight);
+    } else {
+      // If no dimensions were provided, load the image to get them
+      label.textContent = l10n.strings.GetStringFromName("previewTooltip.image.brokenImage");
+      let imgObj = new this.doc.defaultView.Image();
+      imgObj.src = imageUrl;
+      imgObj.onload = () => {
+        imgObj.onload = null;
+        label.textContent = this._getImageDimensionLabel(imgObj.naturalWidth,
+          imgObj.naturalHeight);
+      }
+    }
+    vbox.appendChild(label);
+
+    this.content = vbox;
   },
 
   _getImageDimensionLabel: (w, h) => w + " x " + h,
diff --git a/browser/devtools/styleinspector/rule-view.js b/browser/devtools/styleinspector/rule-view.js
index b8452c670d1..bb55c2891dd 100644
--- a/browser/devtools/styleinspector/rule-view.js
+++ b/browser/devtools/styleinspector/rule-view.js
@@ -1122,7 +1122,7 @@ CssRuleView.prototype = {
     // Test for css transform
     if (property && property.name === "transform") {
       this.previewTooltip.setCssTransformContent(property.value, this.pageStyle,
-        this._viewedElement).then(def.resolve);
+        this._viewedElement).then(def.resolve, def.reject);
       hasTooltip = true;
     }
 
@@ -1164,8 +1164,10 @@ CssRuleView.prototype = {
     }
 
     if (hasTooltip) {
-      this.colorPicker.revert();
-      this.colorPicker.hide();
+      if (this.colorPicker.tooltip.isShown()) {
+        this.colorPicker.revert();
+        this.colorPicker.hide();
+      }
     } else {
       def.reject();
     }
diff --git a/browser/devtools/styleinspector/test/browser_bug726427_csstransform_tooltip.js b/browser/devtools/styleinspector/test/browser_bug726427_csstransform_tooltip.js
index fdec606709c..1283391303b 100644
--- a/browser/devtools/styleinspector/test/browser_bug726427_csstransform_tooltip.js
+++ b/browser/devtools/styleinspector/test/browser_bug726427_csstransform_tooltip.js
@@ -64,106 +64,82 @@ function endTests() {
 }
 
 function testTransformTooltipOnIDSelector() {
-  info("Testing that a transform tooltip appears on the #ID rule");
+  Task.spawn(function*() {
+    info("Testing that a transform tooltip appears on the #ID rule");
 
-  let panel = ruleView.previewTooltip.panel;
-  ok(panel, "The XUL panel exists for the rule-view preview tooltips");
+    let panel = ruleView.previewTooltip.panel;
+    ok(panel, "The XUL panel exists for the rule-view preview tooltips");
+
+    let {valueSpan} = getRuleViewProperty("#testElement", "transform");
+    yield assertTooltipShownOn(ruleView.previewTooltip, valueSpan);
 
-  let {valueSpan} = getRuleViewProperty("#testElement", "transform");
-  assertTooltipShownOn(ruleView.previewTooltip, valueSpan, () => {
     // The transform preview is canvas, so there's not much we can test, so for
     // now, let's just be happy with the fact that the tooltips is shown!
     ok(true, "Tooltip shown on the transform property of the #ID rule");
-    ruleView.previewTooltip.hide();
-    executeSoon(testTransformTooltipOnClassSelector);
-  });
+  }).then(testTransformTooltipOnClassSelector);
 }
 
 function testTransformTooltipOnClassSelector() {
-  info("Testing that a transform tooltip appears on the .class rule");
+  Task.spawn(function*() {
+    info("Testing that a transform tooltip appears on the .class rule");
+
+    let {valueSpan} = getRuleViewProperty(".test-element", "transform");
+    yield assertTooltipShownOn(ruleView.previewTooltip, valueSpan);
 
-  let {valueSpan} = getRuleViewProperty(".test-element", "transform");
-  assertTooltipShownOn(ruleView.previewTooltip, valueSpan, () => {
     // The transform preview is canvas, so there's not much we can test, so for
     // now, let's just be happy with the fact that the tooltips is shown!
     ok(true, "Tooltip shown on the transform property of the .class rule");
-    ruleView.previewTooltip.hide();
-    executeSoon(testTransformTooltipOnTagSelector);
-  });
+  }).then(testTransformTooltipOnTagSelector);
 }
 
 function testTransformTooltipOnTagSelector() {
-  info("Testing that a transform tooltip appears on the tag rule");
+  Task.spawn(function*() {
+    info("Testing that a transform tooltip appears on the tag rule");
+
+    let {valueSpan} = getRuleViewProperty("div", "transform");
+    yield assertTooltipShownOn(ruleView.previewTooltip, valueSpan);
 
-  let {valueSpan} = getRuleViewProperty("div", "transform");
-  assertTooltipShownOn(ruleView.previewTooltip, valueSpan, () => {
     // The transform preview is canvas, so there's not much we can test, so for
     // now, let's just be happy with the fact that the tooltips is shown!
     ok(true, "Tooltip shown on the transform property of the tag rule");
-    ruleView.previewTooltip.hide();
-    executeSoon(testTransformTooltipNotShownOnInvalidTransform);
-  });
+  }).then(testTransformTooltipNotShownOnInvalidTransform);
 }
 
 function testTransformTooltipNotShownOnInvalidTransform() {
-  info("Testing that a transform tooltip does not appear for invalid values");
+  Task.spawn(function*() {
+    info("Testing that a transform tooltip does not appear for invalid values");
 
-  let ruleEditor;
-  for (let rule of ruleView._elementStyle.rules) {
-    if (rule.matchedSelectors[0] === "[attr]") {
-      ruleEditor = rule.editor;
+    let ruleEditor;
+    for (let rule of ruleView._elementStyle.rules) {
+      if (rule.matchedSelectors[0] === "[attr]") {
+        ruleEditor = rule.editor;
+      }
     }
-  }
-  ruleEditor.addProperty("transform", "muchTransform(suchAngle)", "");
+    ruleEditor.addProperty("transform", "muchTransform(suchAngle)", "");
 
-  let {valueSpan} = getRuleViewProperty("[attr]", "transform");
-  assertTooltipNotShownOn(ruleView.previewTooltip, valueSpan, () => {
-    executeSoon(testTransformTooltipOnComputedView);
-  });
+    let {valueSpan} = getRuleViewProperty("[attr]", "transform");
+    let isValid = yield isHoverTooltipTarget(ruleView.previewTooltip, valueSpan);
+    ok(!isValid, "The tooltip did not appear on hover of an invalid transform value");
+  }).then(testTransformTooltipOnComputedView);
 }
 
 function testTransformTooltipOnComputedView() {
-  info("Testing that a transform tooltip appears in the computed view too");
+  Task.spawn(function*() {
+    info("Testing that a transform tooltip appears in the computed view too");
 
-  inspector.sidebar.select("computedview");
-  computedView = inspector.sidebar.getWindowForTab("computedview").computedview.view;
-  let doc = computedView.styleDocument;
+    inspector.sidebar.select("computedview");
+    computedView = inspector.sidebar.getWindowForTab("computedview").computedview.view;
+    let doc = computedView.styleDocument;
 
-  let panel = computedView.tooltip.panel;
-  let {valueSpan} = getComputedViewProperty("transform");
+    let panel = computedView.tooltip.panel;
+    let {valueSpan} = getComputedViewProperty("transform");
+
+    yield assertTooltipShownOn(computedView.tooltip, valueSpan);
 
-  assertTooltipShownOn(computedView.tooltip, valueSpan, () => {
     // The transform preview is canvas, so there's not much we can test, so for
     // now, let's just be happy with the fact that the tooltips is shown!
     ok(true, "Tooltip shown on the computed transform property");
-    computedView.tooltip.hide();
-    executeSoon(endTests);
-  });
-}
-
-function assertTooltipShownOn(tooltip, element, cb) {
-  // If there is indeed a show-on-hover on element, the xul panel will be shown
-  tooltip.panel.addEventListener("popupshown", function shown() {
-    tooltip.panel.removeEventListener("popupshown", shown, true);
-    cb();
-  }, true);
-
-  // Run _showOnHover at stable state after the next refresh driver tick.
-  // This way nothing during reflow or painting should be able to
-  // cancel showing the popup.
-  element.ownerDocument.defaultView.requestAnimationFrame(() => {
-      executeSoon(() => { tooltip._showOnHover(element); });
-    });
-}
-
-function assertTooltipNotShownOn(tooltip, element, cb) {
-  // The only way to make sure the tooltip is not shown is try and show it, wait
-  // for a given amount of time, and then check if it's shown or not
-  tooltip._showOnHover(element);
-  setTimeout(() => {
-    ok(!tooltip.isShown(), "The tooltip did not appear on hover of the element");
-    cb();
-  }, tooltip.defaultShowDelay + 100);
+  }).then(endTests);
 }
 
 function getRule(selectorText) {
diff --git a/browser/devtools/styleinspector/test/browser_bug765105_background_image_tooltip.js b/browser/devtools/styleinspector/test/browser_bug765105_background_image_tooltip.js
index 16ba5bf2ced..85e30833c29 100644
--- a/browser/devtools/styleinspector/test/browser_bug765105_background_image_tooltip.js
+++ b/browser/devtools/styleinspector/test/browser_bug765105_background_image_tooltip.js
@@ -59,100 +59,92 @@ function endTests() {
   finish();
 }
 
-function assertTooltipShownOn(tooltip, element, cb) {
-  // If there is indeed a show-on-hover on element, the xul panel will be shown
-  tooltip.panel.addEventListener("popupshown", function shown() {
-    tooltip.panel.removeEventListener("popupshown", shown, true);
-    cb();
-  }, true);
-  tooltip._showOnHover(element);
-}
-
 function testBodyRuleView() {
-  info("Testing tooltips in the rule view");
+  Task.spawn(function*() {
+    info("Testing tooltips in the rule view");
+    let panel = ruleView.previewTooltip.panel;
 
-  let panel = ruleView.previewTooltip.panel;
+    // Check that the rule view has a tooltip and that a XUL panel has been created
+    ok(ruleView.previewTooltip, "Tooltip instance exists");
+    ok(panel, "XUL panel exists");
 
-  // Check that the rule view has a tooltip and that a XUL panel has been created
-  ok(ruleView.previewTooltip, "Tooltip instance exists");
-  ok(panel, "XUL panel exists");
+    // Get the background-image property inside the rule view
+    let {valueSpan} = getRuleViewProperty("background-image");
+    let uriSpan = valueSpan.querySelector(".theme-link");
+
+    yield assertTooltipShownOn(ruleView.previewTooltip, uriSpan);
 
-  // Get the background-image property inside the rule view
-  let {valueSpan} = getRuleViewProperty("background-image");
-  let uriSpan = valueSpan.querySelector(".theme-link");
-  // And verify that the tooltip gets shown on this property
-  assertTooltipShownOn(ruleView.previewTooltip, uriSpan, () => {
     let images = panel.getElementsByTagName("image");
     is(images.length, 1, "Tooltip contains an image");
-    ok(images[0].src.indexOf("iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHe") !== -1, "The image URL seems fine");
-
-    ruleView.previewTooltip.hide();
+    ok(images[0].getAttribute("src").indexOf("iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHe") !== -1,
+      "The image URL seems fine");
 
+    let onUpdated = inspector.once("inspector-updated");
     inspector.selection.setNode(contentDoc.querySelector(".test-element"));
-    inspector.once("inspector-updated", testDivRuleView);
-  });
+    yield onUpdated;
+  }).then(testDivRuleView);
 }
 
 function testDivRuleView() {
-  let panel = ruleView.previewTooltip.panel;
+  Task.spawn(function*() {
+    let panel = ruleView.previewTooltip.panel;
 
-  // Get the background property inside the rule view
-  let {valueSpan} = getRuleViewProperty("background");
-  let uriSpan = valueSpan.querySelector(".theme-link");
+    // Get the background property inside the rule view
+    let {valueSpan} = getRuleViewProperty("background");
+    let uriSpan = valueSpan.querySelector(".theme-link");
+
+    yield assertTooltipShownOn(ruleView.previewTooltip, uriSpan);
 
-  // And verify that the tooltip gets shown on this property
-  assertTooltipShownOn(ruleView.previewTooltip, uriSpan, () => {
     let images = panel.getElementsByTagName("image");
     is(images.length, 1, "Tooltip contains an image");
-    ok(images[0].src.startsWith("data:"), "Tooltip contains a data-uri image as expected");
-
-    ruleView.previewTooltip.hide();
-
-    testTooltipAppearsEvenInEditMode();
-  });
+    ok(images[0].getAttribute("src").startsWith("data:"), "Tooltip contains a data-uri image as expected");
+  }).then(testTooltipAppearsEvenInEditMode);
 }
 
 function testTooltipAppearsEvenInEditMode() {
-  let panel = ruleView.previewTooltip.panel;
+  Task.spawn(function*() {
+    let panel = ruleView.previewTooltip.panel;
 
-  // Switch one field to edit mode
-  let brace = ruleView.doc.querySelector(".ruleview-ruleclose");
-  waitForEditorFocus(brace.parentNode, editor => {
-    // Now try to show the tooltip
+    info("Switching to edit mode in the rule view");
+    let editor = yield turnToEditMode(ruleView);
+
+    info("Now trying to show the preview tooltip");
     let {valueSpan} = getRuleViewProperty("background");
     let uriSpan = valueSpan.querySelector(".theme-link");
-    assertTooltipShownOn(ruleView.previewTooltip, uriSpan, () => {
-      is(ruleView.doc.activeElement, editor.input,
-        "Tooltip was shown in edit mode, and inplace-editor still focused");
+    yield assertTooltipShownOn(ruleView.previewTooltip, uriSpan);
 
-      ruleView.previewTooltip.hide();
+    is(ruleView.doc.activeElement, editor.input,
+      "Tooltip was shown in edit mode, and inplace-editor still focused");
+  }).then(testComputedView);
+}
 
-      testComputedView();
-    });
-  });
+function turnToEditMode(ruleView) {
+  let def = promise.defer();
+  let brace = ruleView.doc.querySelector(".ruleview-ruleclose");
+  waitForEditorFocus(brace.parentNode, def.resolve);
   brace.click();
+  return def.promise;
 }
 
 function testComputedView() {
-  info("Testing tooltips in the computed view");
+  Task.spawn(function*() {
+    info("Testing tooltips in the computed view");
 
-  inspector.sidebar.select("computedview");
-  computedView = inspector.sidebar.getWindowForTab("computedview").computedview.view;
-  let doc = computedView.styleDocument;
+    inspector.sidebar.select("computedview");
+    computedView = inspector.sidebar.getWindowForTab("computedview").computedview.view;
+    let doc = computedView.styleDocument;
 
-  let panel = computedView.tooltip.panel;
-  let {valueSpan} = getComputedViewProperty("background-image");
-  let uriSpan = valueSpan.querySelector(".theme-link");
+    let panel = computedView.tooltip.panel;
+    let {valueSpan} = getComputedViewProperty("background-image");
+    let uriSpan = valueSpan.querySelector(".theme-link");
+
+    yield assertTooltipShownOn(computedView.tooltip, uriSpan);
 
-  assertTooltipShownOn(computedView.tooltip, uriSpan, () => {
     let images = panel.getElementsByTagName("image");
     is(images.length, 1, "Tooltip contains an image");
-    ok(images[0].src.startsWith("data:"), "Tooltip contains a data-uri in the computed-view too");
 
-    computedView.tooltip.hide();
-
-    endTests();
-  });
+    ok(images[0].getAttribute("src").startsWith("data:"), "Tooltip contains a data-uri in the computed-view too");
+  }).then(endTests);
 }
 
 function getRuleViewProperty(name) {
diff --git a/browser/devtools/styleinspector/test/browser_bug889638_rule_view_color_picker.js b/browser/devtools/styleinspector/test/browser_bug889638_rule_view_color_picker.js
index d79163aba1c..c7eabe9a315 100644
--- a/browser/devtools/styleinspector/test/browser_bug889638_rule_view_color_picker.js
+++ b/browser/devtools/styleinspector/test/browser_bug889638_rule_view_color_picker.js
@@ -105,24 +105,24 @@ function testColorPickerAppearsOnColorSwatchClick() {
 }
 
 function testColorPickerHidesWhenImageTooltipAppears() {
-  let swatch = swatches[0];
-  let bgImageSpan = getRuleViewProperty("background-image").valueSpan;
-  let uriSpan = bgImageSpan.querySelector(".theme-link");
+  Task.spawn(function*() {
+    let swatch = swatches[0];
+    let bgImageSpan = getRuleViewProperty("background-image").valueSpan;
+    let uriSpan = bgImageSpan.querySelector(".theme-link");
+    let tooltip = ruleView.colorPicker.tooltip;
+
+    info("Showing the color picker tooltip by clicking on the color swatch");
+    let onShown = tooltip.once("shown");
+    swatch.click();
+    yield onShown;
+
+    info("Now showing the image preview tooltip to hide the color picker");
+    let onHidden = tooltip.once("hidden");
+    yield assertTooltipShownOn(ruleView.previewTooltip, uriSpan);
+    yield onHidden;
 
-  ruleView.colorPicker.tooltip.once("shown", () => {
-    info("The color picker is shown, now display an image tooltip to hide it");
-    ruleView.previewTooltip._showOnHover(uriSpan);
-  });
-  ruleView.colorPicker.tooltip.once("hidden", () => {
     ok(true, "The color picker closed when the image preview tooltip appeared");
-
-    executeSoon(() => {
-      ruleView.previewTooltip.hide();
-      testPressingEscapeRevertsChanges();
-    });
-  });
-
-  swatch.click();
+  }).then(testPressingEscapeRevertsChanges);
 }
 
 function testPressingEscapeRevertsChanges() {
diff --git a/browser/devtools/styleinspector/test/head.js b/browser/devtools/styleinspector/test/head.js
index 9cdfb09bfd0..692402e3aec 100644
--- a/browser/devtools/styleinspector/test/head.js
+++ b/browser/devtools/styleinspector/test/head.js
@@ -280,3 +280,30 @@ registerCleanupFunction(tearDown);
 
 waitForExplicitFinish();
 
+/**
+ * @return a promise that resolves when the tooltip is shown
+ */
+function assertTooltipShownOn(tooltip, element) {
+  return Task.spawn(function*() {
+    let isTarget = yield isHoverTooltipTarget(tooltip, element);
+    ok(isTarget, "The element is a tooltip target");
+  });
+}
+
+/**
+ * Given a tooltip object instance (see Tooltip.js), checks if it is set to
+ * toggle and hover and if so, checks if the given target is a valid hover target.
+ * This won't actually show the tooltip (the less we interact with XUL panels
+ * during test runs, the better).
+ * @return a promise that resolves when the answer is known. Also, this will
+ * delete to a function in the rule-view which will insert content into the
+ * tooltip
+ */
+function isHoverTooltipTarget(tooltip, target) {
+  if (!tooltip._basedNode || !tooltip.panel) {
+    return promise.reject(new Error("The tooltip passed isn't set to toggle on hover or is not a tooltip"));
+  }
+  // The tooltip delegates to a user defined cb that inserts content in the tooltip
+  // when calling isValidHoverTarget
+  return tooltip.isValidHoverTarget(target);
+}