Problems with XBL

• Actually quite good for many interactive apps (xbl-shapes, Crocodile Maths)

But...

• Many bugs, e.g. prototype chain forking not working, document element can't be bound, etc.
• No data hiding, no public/private interfaces
• No 'real' inheritance (forking bug, but also no virtual methods)
• Forces 'visual-directed programming'. OK for some apps. Not OK for e.g. apps with multiple views -> Want document-view (or MVC) split
• Performance overhead; no C++ implementations possible