don't assign the same normal value for all the other bitmaps, leave them empty (patch 990370)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@28484 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/bmpbuttn.cpp

@@ -137,10 +137,7 @@ bool wxBitmapButton::Create( wxWindow *parent,
         return FALSE;
     }
 
-    m_bmpNormal   =
-    m_bmpDisabled =
-    m_bmpFocus    =
-    m_bmpSelected = bitmap;
+    m_bmpNormal = bitmap;
 
     m_widget = gtk_button_new();