Comment 2 for bug 251617

I encountered the same issue today without warning, except for me, opening a new window from File->New Window did not resolve the issue. Starting Firefox from the command prompt gave no errors or warnings. The only resolution I could find was to first start in safe mode (which had window decoration), then start in normal mode (with all add-ons still enabled). Everything is fine now.

Any idea how to better look for errors/warnings/messages in the future?