Shift-click should actually toggle only within a given group. The new
capability of toggling only a sub-item, brought by commit 970e9ac is
still feasible in 2 steps: first toggling the parent (item group), then
the desired child.
It brings now a third possibility with exclusive toggle among many
children items, without touching other groups and top-level items.
When toggling visibility of a child in an item group, we should also
toggle the visibility of other items in the same group, as well as
top-level items. Otherwise toggling exclusive visibility of any item in
a group is identical to toggling the parent's exclusive visibility,
which is simply absurd.
We still don't touch visibility of items in other groups.
- don't include <gdk-pixbuf/gdk-pixbuf.h> in headers in app/
- instead, include it in many .c files instead of <glib-object.h>,
finally acknowledging the fact that app/ depends on gdk-pixbuf almost
globally
- fix up includes as if libgimpbase depended in GIO, which it soon will
but don't fix it for item trees yet (refactoring only). Kill the
"exclusive liked" function which only existed because it was so easy
to have, but was always utterly useless. Prove me wrong and I will
revive it.
Jehan