diff --git a/docker-compose.yml b/docker-compose.yml
index 8e6a2f46..6eefed89 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -7,7 +7,7 @@ services:
     volumes:
       - ./:/usr/src/app
     ports:
-      - ${XTERMJS_PORT:3000}:3000
+      - ${XTERMJS_PORT:-3000}:3000
     command: ["npm", "start"]
 
   watch:
diff --git a/src/InputHandler.ts b/src/InputHandler.ts
index 2f53cfcb..7405ff9f 100644
--- a/src/InputHandler.ts
+++ b/src/InputHandler.ts
@@ -1284,7 +1284,9 @@ export class InputHandler extends Disposable implements IInputHandler {
           if (this._terminal.element) {
             this._terminal.element.classList.add('enable-mouse-events');
           }
-          this._terminal.selectionManager.disable();
+          if (this._terminal.selectionManager) {
+            this._terminal.selectionManager.disable();
+          }
           this._terminal.log('Binding to mouse events.');
           break;
         case 1004: // send focusin/focusout events
@@ -1474,7 +1476,9 @@ export class InputHandler extends Disposable implements IInputHandler {
           if (this._terminal.element) {
             this._terminal.element.classList.remove('enable-mouse-events');
           }
-          this._terminal.selectionManager.enable();
+          if (this._terminal.selectionManager) {
+            this._terminal.selectionManager.enable();
+          }
           break;
         case 1004: // send focusin/focusout events
           this._terminal.sendFocus = false;
diff --git a/src/Terminal.ts b/src/Terminal.ts
index c1fc8ec8..19b5f125 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -64,10 +64,12 @@ const document = (typeof window !== 'undefined') ? window.document : null;
 const WRITE_BUFFER_PAUSE_THRESHOLD = 5;
 
 /**
- * The number of writes to perform in a single batch before allowing the
- * renderer to catch up with a 0ms setTimeout.
+ * The max number of ms to spend on writes before allowing the renderer to
+ * catch up with a 0ms setTimeout. A value of < 33 to keep us close to
+ * 30fps, and a value of < 16 to try to run at 60fps. Of course, the real FPS
+ * depends on the time it takes for the renderer to draw the frame.
  */
-const WRITE_BATCH_SIZE = 300;
+const WRITE_TIMEOUT_MS = 12;
 
 const MINIMUM_COLS = 2; // Less than 2 can mess with wide chars
 const MINIMUM_ROWS = 1;
@@ -738,6 +740,11 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
     this.mouseHelper = new MouseHelper(this.renderer);
     // apply mouse event classes set by escape codes before terminal was attached
     this.element.classList.toggle('enable-mouse-events', this.mouseEvents);
+    if (this.mouseEvents) {
+      this.selectionManager.disable();
+    } else {
+      this.selectionManager.enable();
+    }
 
     if (this.options.screenReaderMode) {
       // Note that this must be done *after* the renderer is created in order to
@@ -1343,19 +1350,20 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
     }
   }
 
-  protected _innerWrite(): void {
+  protected _innerWrite(bufferOffset: number = 0): void {
     // Ensure the terminal isn't disposed
     if (this._isDisposed) {
       this.writeBuffer = [];
     }
 
-    const writeBatch = this.writeBuffer.splice(0, WRITE_BATCH_SIZE);
-    while (writeBatch.length > 0) {
-      const data = writeBatch.shift();
+    const startTime = Date.now();
+    while (this.writeBuffer.length > bufferOffset) {
+      const data = this.writeBuffer[bufferOffset];
+      bufferOffset++;
 
       // If XOFF was sent in order to catch up with the pty process, resume it if
-      // the writeBuffer is empty to allow more data to come in.
-      if (this._xoffSentToCatchUp && writeBatch.length === 0 && this.writeBuffer.length === 0) {
+      // we reached the end of the writeBuffer to allow more data to come in.
+      if (this._xoffSentToCatchUp && this.writeBuffer.length === bufferOffset) {
         this.handler(C0.DC1);
         this._xoffSentToCatchUp = false;
       }
@@ -1373,12 +1381,17 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
 
       this.updateRange(this.buffer.y);
       this.refresh(this._refreshStart, this._refreshEnd);
+
+      if (Date.now() - startTime >= WRITE_TIMEOUT_MS) {
+        break;
+      }
     }
-    if (this.writeBuffer.length > 0) {
+    if (this.writeBuffer.length > bufferOffset) {
       // Allow renderer to catch up before processing the next batch
-      setTimeout(() => this._innerWrite(), 0);
+      setTimeout(() => this._innerWrite(bufferOffset), 0);
     } else {
       this._writeInProgress = false;
+      this.writeBuffer = [];
     }
   }
 
diff --git a/src/renderer/Renderer.ts b/src/renderer/Renderer.ts
index 02328877..b8ef87aa 100644
--- a/src/renderer/Renderer.ts
+++ b/src/renderer/Renderer.ts
@@ -70,7 +70,7 @@ export class Renderer extends EventEmitter implements IRenderer {
     // Detect whether IntersectionObserver is detected and enable renderer pause
     // and resume based on terminal visibility if so
     if ('IntersectionObserver' in window) {
-      const observer = new IntersectionObserver(e => this.onIntersectionChange(e[0]), { threshold: 0 });
+      const observer = new IntersectionObserver(e => this.onIntersectionChange(e[e.length - 1]), { threshold: 0 });
       observer.observe(this._terminal.element);
       this.register({ dispose: () => observer.disconnect() });
     }
diff --git a/src/ui/MouseZoneManager.ts b/src/ui/MouseZoneManager.ts
index a232f5b9..79022723 100644
--- a/src/ui/MouseZoneManager.ts
+++ b/src/ui/MouseZoneManager.ts
@@ -23,6 +23,7 @@ export class MouseZoneManager extends Disposable implements IMouseZoneManager {
 
   private _areZonesActive: boolean = false;
   private _mouseMoveListener: (e: MouseEvent) => any;
+  private _mouseLeaveListener: (e: MouseEvent) => any;
   private _clickListener: (e: MouseEvent) => any;
 
   private _tooltipTimeout: number = null;
@@ -38,6 +39,7 @@ export class MouseZoneManager extends Disposable implements IMouseZoneManager {
 
     // These events are expensive, only listen to it when mouse zones are active
     this._mouseMoveListener = e => this._onMouseMove(e);
+    this._mouseLeaveListener = e => this._onMouseLeave(e);
     this._clickListener = e => this._onClick(e);
   }
 
@@ -89,6 +91,7 @@ export class MouseZoneManager extends Disposable implements IMouseZoneManager {
     if (!this._areZonesActive) {
       this._areZonesActive = true;
       this._terminal.element.addEventListener('mousemove', this._mouseMoveListener);
+      this._terminal.element.addEventListener('mouseleave', this._mouseLeaveListener);
       this._terminal.element.addEventListener('click', this._clickListener);
     }
   }
@@ -97,6 +100,7 @@ export class MouseZoneManager extends Disposable implements IMouseZoneManager {
     if (this._areZonesActive) {
       this._areZonesActive = false;
       this._terminal.element.removeEventListener('mousemove', this._mouseMoveListener);
+      this._terminal.element.removeEventListener('mouseleave', this._mouseLeaveListener);
       this._terminal.element.removeEventListener('click', this._clickListener);
     }
   }
@@ -169,6 +173,18 @@ export class MouseZoneManager extends Disposable implements IMouseZoneManager {
     }
   }
 
+  private _onMouseLeave(e: MouseEvent): void {
+    // Fire the hover end callback and cancel any existing timer if the mouse
+    // leaves the terminal element
+    if (this._currentZone) {
+      this._currentZone.leaveCallback();
+      this._currentZone = null;
+      if (this._tooltipTimeout) {
+        clearTimeout(this._tooltipTimeout);
+      }
+    }
+  }
+
   private _onClick(e: MouseEvent): void {
     // Find the active zone and click it if found
     const zone = this._findZoneEventAt(e);