correct check for double buffered rendering

Change-Id: I52972cb477c77a86fa04aa876717db9740cc0113
don't put the parent window as child into itself

Change-Id: I961b92d47c35d63fa852bab2b478b93314e9add7
fix another crash on exit

Change-Id: I580d17b16760516b73ac9f882fd8f9707ce6337b
we only want a fb that allows window rendering

Change-Id: I13d58c941e6a2411c3840b9efd341a4b827afc93