avoid setting negative size

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59022 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/editlbox.cpp

@@ -172,6 +172,7 @@ public:
 #else
          w -= 2*wxSystemSettings::GetMetric(wxSYS_VSCROLL_X);
 #endif
+         if (w < 0) w = 0;
          SetColumnWidth(0, w);
     }