Apparently GDK/Win32 sends the "grab-broken-event" signal before the "clicked"
signal. This has only been changed since GTK4 so far.
Anyway the bottom line is that GimpContainerPopup would process a handled on
"clicked", using the object destroyed when "grab-broken-event" happened as
callback data. The solution is to make sure that the object stays alive long
enough. So I'm changing gimp_editor_add_button() to connect to signals with
g_signal_connect_object() (since all usage of this function was used with
GObject callback data, it was not a problem).
See discussion in !815.
As a side change, gimp_container_popup_dialog_clicked() should emit the
"cancel", not "confirm". This part was taken from MR !815 by Lloyd Konneker.
(cherry picked from commit f77f772f56)
In the gradient-tool editor, when responding to an endpoint size-
entry "changed" signal, make sure there is a selected handle, and
bail otherwise. We can receive a "changed" signal without a
selected handle, if the endpoint is deselected while a change to
the size-entry's value is in progress, causing the the tool GUI to
be unmapped, and the changed value to be committed.
Rename gimpblendtool{.c,-editor.{c,h}} to
gimpgradientool{.c,-editor.{c,h}}. Note that this commit only
renames the files; the actual changes are done in the next commit,
so that git doesn't consider them new files.
