The fix for 6714678 added the system property sun.awt.disableGrab in order to be able to disable grabbing the X server in some cases (particularly, when handling the popups - like combobox popups, etc.).
Other parts of the AWT library make use of grabbing as well - one example is the Drag'N'Drop support. We need to be able to disable grabbing in these cases too, in order to simplify debugging of applications that use DND. Either an additional system property needs to be introduced, or the grab should be disabled based on the existing (sun.awt.disableGrab) system property's value.