Remove unused member variable from wxSimpleCheckBox (used in wxPGCheckBoxEditor).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78269 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/propgrid/editors.cpp

@@ -1533,8 +1533,6 @@ private:
     }
     void OnLeftClickActivate( wxCommandEvent& evt );
 
-    static wxBitmap* ms_doubleBuffer;
-
     DECLARE_EVENT_TABLE()
 };
 
@@ -1551,11 +1549,8 @@ END_EVENT_TABLE()
 
 wxSimpleCheckBox::~wxSimpleCheckBox()
 {
-    wxDELETE(ms_doubleBuffer);
 }
 
-wxBitmap* wxSimpleCheckBox::ms_doubleBuffer = NULL;
-
 void wxSimpleCheckBox::OnPaint( wxPaintEvent& WXUNUSED(event) )
 {
     wxRect rect(GetClientSize());