Okay, my bad. InitShow happens after Visible. And InitShow also does
some layouting. Emitting the created callback on InitShow means sending
more accurate sizes, etc. The different in sizes is 0 for combo boxes,
but significant for custom controls like color picker, etc. So emit
created callback on InitShow to keep custom controls working.

Change-Id: I40b6a18b917dff0eebcfd4c273f3399f3bdc7456