diff --git a/browser/devtools/webide/content/webide.xul b/browser/devtools/webide/content/webide.xul
index 859570a439a..ca663b807c7 100644
--- a/browser/devtools/webide/content/webide.xul
+++ b/browser/devtools/webide/content/webide.xul
@@ -193,7 +193,7 @@
   </popupset>
 
   <notificationbox flex="1" id="notificationbox">
-    <hbox flex="1">
+    <hbox flex="1" id="deck-panels">
       <vbox id="project-listing-panel" class="project-listing" flex="1">
         <div id="project-listing-wrapper">
           <iframe id="project-listing-panel-details" flex="1" src="project-listing.xhtml"/>
diff --git a/browser/devtools/webide/themes/webide.css b/browser/devtools/webide/themes/webide.css
index 96c4cfea528..b5ab95aaca9 100644
--- a/browser/devtools/webide/themes/webide.css
+++ b/browser/devtools/webide/themes/webide.css
@@ -324,13 +324,15 @@ panel > .panel-arrowcontainer > .panel-arrowcontent {
 
 /* Toolbox */
 
-#notificationbox[toolboxfullscreen] > .devtools-horizontal-splitter,
-#notificationbox[toolboxfullscreen] > #deck,
-#notificationbox[toolboxfullscreen] > #deck > iframe {
+#notificationbox[toolboxfullscreen] > .devtools-horizontal-splitter {
   min-height: 0;
   max-height: 0;
 }
 
+#notificationbox[toolboxfullscreen] > #deck-panels {
+  display: none;
+}
+
 #notificationbox[toolboxfullscreen] > #toolbox {
   -moz-box-flex: 1;
 }