In both browsers currently supported (Chrome and Firefox) I should test these things:
- Activate the extension
- click a fullscreen button (eg. on youtube)
- Try all three options (Windowed, in window and fullscreen)
- Every option should transform the window into the right "format"
- Click the "un-fullscreen" button, and it should transform back to a normal tab again.
- Activate the extension
- Go to youtube
- Press the "Browser action" (thus, disabling the extension on youtube)
- Press the fullscreen button
- No option menu should appear now, it goes into normal fullscreen
- Go out of fullscreen again
- Refresh the page
- Press the fullscreen button
- No option menu should appear now, it goes into normal fullscreen
- Go out of fullscreen again