When using the latests builds (Orbeon Forms dev-3.7.1.200905131351), in certain pages that use the instance inspector such as
http://localhost:8080/orbeon/xforms-todo/I get following error:
XPath syntax error at char 8 in {@ui:done}:
Prefix ui has not been declared
I get the same with my own pages since I use namespace prefixes for my domain instances.