account for DrawThemeParentBackground() returning S_FALSE

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@37388 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/tbar95.cpp

@@ -1368,9 +1368,12 @@ void wxToolBar::OnEraseBackground(wxEraseEvent& event)
             {
                 HRESULT
                     hr = theme->DrawThemeParentBackground(GetHwnd(), hdc, &rect);
-                if ( SUCCEEDED(hr) )
+                if ( hr == S_OK )
                     return;
 
+                // it can also return S_FALSE which seems to simply say that it
+                // didn't draw anything but no error really occurred
+                if ( FAILED(hr) )
                     wxLogApiError(_T("DrawThemeParentBackground(toolbar)"), hr);
             }
         }