We're working on a UI at work and people want to have the number of tabs in a certain area be flexible width so that in certain situations depending on the title length and the number of tabs, the tab row might end up filling 2 or even 3 lines.
I'm wondering if it's ever ok to have multiple rows of tabs; to me it seems like it breaks the tab metaphor and then you have to worry about tabs changing locations.
At the same time, though, I'm not sure of a good alternative other than a list or accordion.