Collab ui2 (#3357)

* Clickable context menus & movable panels – what will they think of
next?!

Release Notes:

- N/A

crates/workspace2/src/workspace2.rs

@@ -813,7 +813,9 @@ impl Workspace {
             DockPosition::Right => &self.right_dock,
         };
 
-        dock.update(cx, |dock, cx| dock.add_panel(panel, cx));
+        dock.update(cx, |dock, cx| {
+            dock.add_panel(panel, self.weak_self.clone(), cx)
+        });
     }
 
     pub fn status_bar(&self) -> &View<StatusBar> {