Fixed memory leak when setting new wxMask for wxBitmap

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@20236 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -229,6 +229,7 @@ wxMSW:
   hotkey
 - fix for multiple consecutive groups of radiobuttons
 - fix for incorrect display of tooltips in non English locales (Niki Spahiev)
+- fixed memory leak when setting new wxMask for wxBitmap
 
 wxMotif:
 

src/msw/bitmap.cpp

@@ -1088,6 +1088,7 @@ void wxBitmap::SetMask(wxMask *mask)
 {
     EnsureHasData();
 
+    delete GetBitmapData()->m_bitmapMask ;
     GetBitmapData()->m_bitmapMask = mask;
 }