Centre() centers the window centre and not the upper left corner

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4517 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/wincmn.cpp

@@ -354,7 +354,9 @@ void wxWindowBase::Centre(int direction)
         yNew += posParent.y;
     }
 
-    Move(xNew, yNew);
+    // move the centre of this window to this position (not the upper left
+    // corner as it was done before)
+    Move(xNew - width / 2, yNew - height / 2);
 }
 
 // fits the window around the children