RubyMine 4.0.2 hover, Cannot find declaration for field

When I over over a variable in the editor, I get a popup that says:
Cannot find declaration for field: @cart, ...

When in the debugger the: "Cannot find declaration for field" pops up, disappears and the inspector popup displays, when I move the cursor to click on the + icon to expand the inspector it disappears, before I can click on it.

See attached images


This wokred fine in 3.2.4, not working in 4.0.2.


Running OS X 10.7.3, ruby 1.9.2-p290, rails 3.1.3.