Yeah, it could be really complicated. Although in reality many (or perhaps most) personal/small project don't care or don't check license compatibility between each library/used source code. But AFAIK rewriting source code usually is legally acceptable. BPIP will have to do that anyway unless they want to bundle jQuery on their extension.
Yeah we don't really want jQuery. I'll take a look at what the enhanced merit UI does and if/how that functionality fits into our extension. I assume you wouldn't have a problem if we steal the idea but not the code?
No problem. In fact, i do not consider that as stealing.
