[glade--]weird fake widget with unfilled vboxes and hboxes

If I leave a vbox and/or hbox unfilled with glade, and then run glademm, I get this fake object inserted, which causes compilation errors.
   hbox1->pack_start(*WidgetqDZqDHQ);
   vbox1->pack_start(*WidgetQHGqDHQ);

These fake widget objects appear nowhere else in the mainWindow_glade.cc file, nor in my .glade file.  So glademm appears to be making them up, but is

If I comment those lines out...all compiles fine, and the program runs fine too.

Mark