“Quote” pop-up element is can get obscured by Opera’s copy/search pop-up menu. You can bypass this by pressing ESC, though.
Adding on that, “Summary” bb-code is successfully hiding content in preview, but fails to do that on page
[details=Summary]http://i.imgur.com/tTjt3A0.jpg
[/details]
Make sure that summary is in a new line.
Successful:
test
[details=Summary]text[/details]
Fails:
test
[details=Summary]text[/details]
I can clearly see from the code that element in question is getting “caught” by a paragraph, but still this behaivor is not something user will consider normal, especially when there is an example on the bottom of the screen (preview) 