Somehow the toggle actions were not working correctly on GimpMenu popped up e.g.
as dockbook menus (but it was fine in the GimpMenuBar). I straightened up the
code to be a bit clearer. I also rely on the "toggled" signal rather than
"change-state" (the latter is supposed to happen before state change actually
happen). It now works much better.
Several menus can be triggered either as popups on their own when right-clicking
the dockable or on items, or as a submenu in the docks main menu.
In the former case, we want the menu items to be at the root level, whereas in
the latter case, we want them inside a properly named submenu.
To handle this, I wrap these in a properly labelled <submenu> in the .ui files,
and I add a boolean flag to gimp_menu_shell_fill() which will drop the top
submenu if and only if this is the only top item. I use this flag only when
using these menus as popup menu on their own.
Also fixing a few memory leaks around these pieces of code.
… group name.
The gradient editor submenu add 2 submenus with changing names. It was using
again bogus actions: "gradient-editor-blending-func" and
"gradient-editor-coloring-type" do nothing except for being used as name
holders.
Instead I add the concept of group name for GimpRadioAction-s and when I use a
radio action attribute as <submenu>, this submenu will use the group name (and
sync with it, if it changes).
I only translated the undo menu into GtkBuilder's .ui format for now.
The only missing part is that the icon is now shown.
Note that in various parts, I don't rely anymore on a bogus menu action (i.e.
"undo-popup" action in this case) which does nothing but has an associated label
and icon. I simply add the label and icon as submenu attribute directly in the
.ui file, which is translatable and whose strings should be parsed by gettext.
Eventually I'll just get rid of all the various "*-popup" or "*-menu" bogus
actions.
The new GimpMenu is derived from GtkMenu. Both GimpMenu and GimpMenuBar are now
implementing GimpMenuShell which allows to share a lot of the logic for filling
the menus, adding items, etc.
