reenabled WM_MOUSELEAVE event handling (patch 1104551); moved duplicated code in its handler in a new GenerateMouseLeave() method

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31480 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/window.h

@@ -411,6 +411,9 @@ public:
     // check if mouse is in the window
     bool IsMouseInWindow() const;
 
+    // synthesize a wxEVT_LEAVE_WINDOW event and set m_mouseInWindow to false
+    void GenerateMouseLeave();
+
     // virtual function for implementing internal idle
     // behaviour
     virtual void OnInternalIdle() ;