VST2 Client: Fix popupmenu window location in VST2 plugins under the AudioPluginHost

modules/juce_gui_basics/native/x11/juce_linux_XWindowSystem.cpp

@@ -1864,7 +1864,9 @@ Rectangle<int> XWindowSystem::getWindowBounds (::Window windowH, ::Window parent
         }
         else
         {
-            parentScreenPosition = Point<int> (rootX, rootY);
+            // XGetGeometry returns wx and wy relative to the parent window's origin.
+            // XTranslateCoordinates returns rootX and rootY relative to the root window.
+            parentScreenPosition = Point<int> (rootX - wx, rootY - wy);
         }
     }