in the previous version the buttons were added to the plugin object itself instead to the stage by mistake. And that allows moving them by moving the plugin object. But they were indented to be on the 'stage' level above all other elements and this was corrected in the last release. E.g. when the buttons were moved or at the wrong place, then some functionality (e.g. the xml editor) might not work anymore because of some buttons might be not reachable anymore (e.g. because of being overlapped/hidden).