Index: src/wp-includes/js/media-views.js
===================================================================
--- src/wp-includes/js/media-views.js	(revision 28187)
+++ src/wp-includes/js/media-views.js	(working copy)
@@ -3270,6 +3270,7 @@
 		localDrag: false,
 		overContainer: false,
 		overDropzone: false,
+		draggingFile: null,
 
 		initialize: function() {
 			var self = this;
@@ -3309,6 +3310,21 @@
 			return supports;
 		},
 
+		isDraggingFile: function( event ) {
+			if ( this.draggingFile !== null ) {
+				return this.draggingFile;
+			}
+
+			if ( _.isUndefined( event.originalEvent ) || _.isUndefined( event.originalEvent.dataTransfer ) ) {
+				return false;
+			}
+
+			this.draggingFile = _.indexOf( event.originalEvent.dataTransfer.types, 'Files' ) > -1 &&
+				_.indexOf( event.originalEvent.dataTransfer.types, 'text/plain' ) === -1;
+
+			return this.draggingFile;
+		},
+
 		refresh: function( e ) {
 			var dropzone_id;
 			for ( dropzone_id in this.dropzones ) {
@@ -3320,6 +3336,10 @@
 				$( e.target ).closest( '.uploader-editor' ).toggleClass( 'droppable', this.overDropzone );
 			}
 
+			if ( ! this.overContainer && ! this.overDropzone ) {
+				this.draggingFile = null;
+			}
+
 			return this;
 		},
 
@@ -3383,8 +3403,8 @@
 			return this;
 		},
 
-		containerDragover: function() {
-			if ( this.localDrag ) {
+		containerDragover: function( event ) {
+			if ( this.localDrag || ! this.isDraggingFile( event ) ) {
 				return;
 			}
 
@@ -3399,13 +3419,13 @@
 			_.delay( _.bind( this.refresh, this ), 50 );
 		},
 
-		dropzoneDragover: function( e ) {
-			if ( this.localDrag ) {
+		dropzoneDragover: function( event ) {
+			if ( this.localDrag || ! this.isDraggingFile( event ) ) {
 				return;
 			}
 
 			this.overDropzone = true;
-			this.refresh( e );
+			this.refresh( event );
 			return false;
 		},
 
Index: src/wp-includes/js/tinymce/plugins/wordpress/plugin.js
===================================================================
--- src/wp-includes/js/tinymce/plugins/wordpress/plugin.js	(revision 28187)
+++ src/wp-includes/js/tinymce/plugins/wordpress/plugin.js	(working copy)
@@ -317,7 +317,7 @@
 			dom.bind( doc, 'dragstart dragend dragover drop', function( event ) {
 				if ( typeof window.jQuery !== 'undefined' ) {
 					// Trigger the jQuery handlers.
-					window.jQuery( document ).triggerHandler( event.type );
+					window.jQuery( document ).trigger( new window.jQuery.Event( event ) );
 				}
 			});
 		}