Not sure if this problem is caused by extlib or dojo (I am using 1.6.1)
I created an xpage with a dojo stack container (& child dojo stack panes). When I added a dojo number spinner the browser reports a error in dojo.js (line 81) "this._set is not a function".
The error only occurs if you have both controls on an xpage (if the numberspinner is outside the stack pane it will still display, but not if it inside a stack pane)
example code -
1. Only numberspinner - works
2. Only stack pane - works
3. numberspinner outside stack pane - works but error message
4. numberspinner inside stack pane - fails to display number spinner