Ok, this is what needs to be done for Qt and Gtk2:
1.main.pp TMainIDE.GetActiveDesignerSkipMainBar always returns nil (gtk2 and Qt), that's why shortcuts does not work , mean copy paste of components inside designed form via keyboard. With menu it does work. So, in this function sparta must return current designer somehow. I'm not sure that shortcuts works on win32 too because of this, or win32 contains some extra magic.
2.sparta_ResizerFrame.pas im procedure TResizerFrame.TryBoundDesignedForm;
{$IF DEFINED(LCLGtk2) OR DEFINED(LCLQt)}
pClient.SendToBack; // <--- this is a must.
{$ENDIF}
pClient.BringToFront;