Most YouTube Videos have keywords. If they are allowed, all is fine. Else, blocks with a page displaying the keywords.
Double-click started full-screen (see 0.4.0 for the problem)
Fullscreen mode did not trigger keyword block, as it did not update keywords, so its button was made invisible.
There was no easy way to go back to before the blocked page.
broke pages with embedded videos
had allowed another way to play videos without keywords
Played videos without keywords
lacked multiprocess + private browsing flags
Lacked blacklist
did not handle keywords = '' correctly