fix: Issue with focus setting on widget after relocating to a new splitter
The bug is a problem where the widget was not receiving focus after being moved to a new splitter (not clear why). The solution involves connecting it to a signal, introducing a delay for the focus request.
The deleteLater call has been removed. This isn't necessary because the old splitter after lose the remaining widget will subsequently trigger the childEvent with count == 0 and be deleted.