added wxWindow::HasFocus() for more convenient way of determining if a (possibly composite) window has focus

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51308 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/window.h

@@ -620,6 +620,11 @@ public:
 
     static wxWindow *DoFindFocus() /* = 0: implement in derived classes */;
 
+        // return true if the window has focus (handles composite windows
+        // correctly - returns true if GetMainWindowOfCompositeControl()
+        // has focus)
+    virtual bool HasFocus() const;
+
         // can this window have focus in principle?
         //
         // the difference between AcceptsFocus[FromKeyboard]() and CanAcceptFocus