+// We operate with pointer to members of wxEvtHandler (such functions are used
+// as event handlers in the event tables or as arguments to Connect()) but by
+// default MSVC uses a restricted (but more efficient) representation of
+// pointers to members which can't deal with multiple base classes. To avoid
+// mysterious (as the compiler is not good enough to detect this and give a
+// sensible error message) errors in the user code as soon as it defines
+// classes inheriting from both wxEvtHandler (possibly indirectly, e.g. via
+// wxWindow) and something else (including our own wxTrackable but not limited
+// to it), we use the special MSVC keyword telling the compiler to use a more
+// general pointer to member representation for the classes inheriting from
+// wxEvtHandler.
+#ifdef __VISUALC__
+ #define wxMSVC_FWD_MULTIPLE_BASES __multiple_inheritance
+#else
+ #define wxMSVC_FWD_MULTIPLE_BASES
+#endif
+
+class WXDLLIMPEXP_FWD_BASE wxMSVC_FWD_MULTIPLE_BASES wxEvtHandler;