diff --git a/Fltk/graphicWindow.cpp b/Fltk/graphicWindow.cpp
index 77ced1497384370a99df40f1955b8f87411b0630..ed3ada25d685ffe668872c5bbba1e289abcb28da 100644
--- a/Fltk/graphicWindow.cpp
+++ b/Fltk/graphicWindow.cpp
@@ -3116,6 +3116,8 @@ void graphicWindow::showMenu()
     int maxw = _win->w();
     if(width > maxw) width = maxw / 2;
     setMenuWidth(width);
+    // FIXME: this is necessary until resizing a 0-sized group works in fltk
+    _onelab->rebuildTree(true);
   }
 }