Fix diagnostics tab overlay
tabForToolViewAdded needs to be delayed emitted so that DiagnosticsView can connect to the signal before it's emitted.
Also, fix the positioning of DiagTabOverlay. It needs to be (0,0) in parent now
tabForToolViewAdded needs to be delayed emitted so that DiagnosticsView can connect to the signal before it's emitted.
Also, fix the positioning of DiagTabOverlay. It needs to be (0,0) in parent now