ComboBox submenus

[Carlos Pereira <jose carlos pereira ist utl pt>]

My ComboBox submenus are working fine. There are however a couple of 
visual details that could be improved, in my opinion.

I am sending as attachement a small (70 lines) working example  (C + 
makefile) showing my points:

1) Submenus should look the same in ComboBox and Popup menus.  Therefore 
Main 1 and Main 2 (see working example or tree store below) should not 
appear repeated again in the submenus. Even if they were there, they 
should not be selectable as they are only entry points to submenus. The 
workaround I know is: when users select Main 1 or Main 2, just select a 
sensible default instead, such as the first main item, the last chosen 
item, the first item in the submenu.

2) All pop up menus should have the same width. Currently this deppends 
entirely of the size of the label strings. The submenus for Main 1 and 
Main 2 have entirely different widths, and I think this looks 
unprofessional. The workaround I know is: add whitespaces at the end of 
the label strings.

3) The main menu has a large space between the labels and the  submenu 
arrows, I guess this is probably related with accelerators (which I am 
not using here) but it looks a bit ugly. I don't know any workaround for 
this. Pop up menus have the same issue.

I am planning to fill a bug report about this. If someone can prove me 
wrong or knows a solution for any of the three points discussed above, I 
would be glad to know.

Thanks!
Carlos

store = gtk_tree_store_new (1, G_TYPE_STRING);
gtk_tree_store_append (store, &iter, NULL);
gtk_tree_store_set (store, &iter, 0, "Main 0", -1);

gtk_tree_store_append (store, &iter, NULL);
gtk_tree_store_set (store, &iter, 0, "Main 1", -1);
gtk_tree_store_append (store, &child, &iter);
gtk_tree_store_set (store, &child, 0, "Short 1:0", -1);
gtk_tree_store_append (store, &child, &iter);
gtk_tree_store_set (store, &child, 0, "Short 1:1", -1);
gtk_tree_store_append (store, &child, &iter);
gtk_tree_store_set (store, &child, 0, "Short 1:2", -1);

gtk_tree_store_append (store, &iter, NULL);
gtk_tree_store_set (store, &iter, 0, "Main 2", -1);
gtk_tree_store_append (store, &child, &iter);
gtk_tree_store_set (store, &child, 0, "Very very long 2:0", -1);
gtk_tree_store_append (store, &child, &iter);
gtk_tree_store_set (store, &child, 0, "Very very long 2:1", -1);