Merge pull request #16936 from atom/fb-mdt-fix-16933

Fix bug caused by dragging file from desktop through dock handle

src/dock.js

@@ -233,7 +233,7 @@ module.exports = class Dock {
         ),
         $(DockToggleButton, {
           ref: 'toggleButton',
-          onDragEnter: this.handleToggleButtonDragEnter,
+          onDragEnter: this.state.draggingItem ? this.handleToggleButtonDragEnter : null,
           location: this.location,
           toggle: this.toggle,
           dockIsVisible: shouldBeVisible,
@@ -779,7 +779,10 @@ class DockToggleButton {
         {
           ref: 'innerElement',
           className: `atom-dock-toggle-button-inner ${this.props.location}`,
-          on: {click: this.handleClick, dragenter: this.handleDragEnter}
+          on: {
+            click: this.handleClick,
+            dragenter: this.props.onDragEnter
+          }
         },
         $.span({
           ref: 'iconElement',
@@ -808,10 +811,6 @@ class DockToggleButton {
   handleClick () {
     this.props.toggle()
   }
-
-  handleDragEnter () {
-    this.props.onDragEnter()
-  }
 }
 
 // An etch component that doesn't use etch, this component provides a gateway from JSX back into