Element* getChildElementAtIdx(size_t idx) const; size_t getChildCount() const;
Problem is that tolua++ doesn't understand size_t, and will treat it as a "userdata". The fix is to replace with these lines instead:
Element* getChildElementAtIdx(unsigned int idx) const; unsigned int getChildCount() const;
Not totally correct since size_t doesn't have to be unsigned int, but if the user is on a 64-bit system and have more than 4,294,967,296 child windows, they probably have other issues.
OS: Linux, OS build: , Platform: AMD64