With our old code, we needed dummy actions for every submenu. This is not needed
anymore. Actions are only for end menu items (items which actually do something,
not just open a submenu).
Get rid of them all, as well as the code to ignore any action ending with such
suffixes in action-listing pieces of code.
In some cases, in particular for actions generated from plug-in
procedure right now, we were displaying the reason of the insensitivity
(typically right now, only the drawable type is cited). This was done by
appending the reason to the tooltip, separated by 2 newlines, which
resulted in extra ugly design, no nice way to style this info directly
(with pango for instance if the widget display allows it, or on a
separate info widget in a possible future, or whatnot).
Also it would mean that the action search could match a disabled action
by mistake if a search word happens to be in the reason message.
This improves the situation with the following changes:
* gimp_action_set_sensitive() now takes an optional reason string to set
the reason message.
* Same for gimp_action_group_set_action_sensitive().
* gimp_action_get_sensitive() returns an optional reason string.
* gimp_procedure_get_sensitive()'s tooltip return value now becomes a
reason (it won't contain anymore the tooltip and the reason
concatenated, only the reason for separate processing).
Add gimp_item_get_merged_color_tag(), which returns the color tag
of the nearest ancestor (including the current item) that has a
color tag other than NONE. Use this function in GimpItemTreeView,
instead of gimp_item_get_color_tag(), to set the cell color of
items, so that item's with a NONE color tag inherit the color of
their parent. Add a boolean "inherited" parameter to
gimp_get_color_tag_color(), which indicates if the color tag is the
item's actual color tag, or an inherited color tag, and modify the
returned color accordingly, so that inherited colors are less
saturated/lighter than non-inherited ones.
Add property "color-tag" of type enum GimpColorTag to GimpItem so all
layers, channels and paths can be tagged with a color.
For interoperability, use the color list from Krita which is a
superset of Photoshop's colors.
Features a "Color Tag" submenu in the layers, channels and paths
menus, a row of color radio buttons in the properties dialogs,
undo and PDB API.
As a side effect, some common code is now factores out into
items-actions.[ch] and items-commands.[ch] which adds visible, linked
and lock actions for layers and channels.
Jehan