Restore intellihide grabs check for PanelMenuButton

intellihide.js

@@ -20,6 +20,7 @@ const Clutter = imports.gi.Clutter;
 const Meta = imports.gi.Meta;
 const Shell = imports.gi.Shell;
 
+const GrabHelper = imports.ui.grabHelper;
 const Layout = imports.ui.layout;
 const Main = imports.ui.main;
 const OverviewControls = imports.ui.overviewControls;
@@ -32,10 +33,12 @@ const Utils = Me.imports.utils;
 
 //timeout intervals
 const CHECK_POINTER_MS = 200;
+const CHECK_GRAB_MS = 400;
 const POST_ANIMATE_MS = 50; 
 const MIN_UPDATE_MS = 250;
 
 //timeout names
+const T1 = 'checkGrabTimeout';
 const T2 = 'limitUpdateTimeout';
 const T3 = 'postAnimateTimeout';
 
@@ -295,7 +298,8 @@ var Intellihide = Utils.defineClass({
     },
 
     _checkIfShouldBeVisible: function(fromRevealMechanism) {
-        if (Main.overview.visibleTarget || this._dtpPanel.taskbar.previewMenu.opened || this._panelBox.get_hover()) {
+        if (Main.overview.visibleTarget || this._dtpPanel.taskbar.previewMenu.opened || 
+            this._panelBox.get_hover() || this._checkIfGrab()) {
             return true;
         }
 
@@ -317,6 +321,17 @@ var Intellihide = Utils.defineClass({
         return !this._windowOverlap;
     },
 
+    _checkIfGrab: function() {
+        if (GrabHelper._grabHelperStack.some(gh => this._panelBox.contains(gh._owner))) {
+            //there currently is a grab on a child of the panel, check again soon to catch its release
+            this._timeoutsHandler.add([T1, CHECK_GRAB_MS, () => this._queueUpdatePanelPosition()]);
+
+            return true;
+        }
+
+        return false;
+    },
+
     _revealPanel: function(immediate) {
         this._animatePanel(0, immediate);
     },

panel.js

@@ -267,7 +267,6 @@ var dtpPanelWrapper = Utils.defineClass({
         this._setAppmenuVisible(false);
         if(this.appMenu)
             this.panel._leftBox.add_child(this.appMenu.container);
-        this.taskbar.destroy();
 
         if (this.startIntellihideId) {
             Mainloop.source_remove(this.startIntellihideId);
@@ -288,6 +287,8 @@ var dtpPanelWrapper = Utils.defineClass({
             this.dynamicTransparency.destroy();
         }
 
+        this.taskbar.destroy();
+
         // reset stored icon size  to the default dash
         Main.overview.dashIconSize = Main.overview._controls.dash.iconSize;
 

panelManager.js

@@ -282,7 +282,7 @@ var dtpPanelManager = Utils.defineClass({
     },
 
     _getBoxPointerPreferredHeight: function(boxPointer, alloc, monitor) {
-        if (boxPointer._dtpInPanel && this._dtpSettings.get_boolean('intellihide')) {
+        if (boxPointer._dtpInPanel && boxPointer.sourceActor && this._dtpSettings.get_boolean('intellihide')) {
             monitor = monitor || Main.layoutManager.findMonitorForActor(boxPointer.sourceActor);
             let excess = alloc.natural_size + this._dtpSettings.get_int('panel-size') + 10 - monitor.height; // 10 is arbitrary