When adding new input sources, the first dialog shows a list of
languages, when single clicking one item you go to a subdialog
that has a 'go back' item, that item only works if double-clicking
it, but that is unintuitive because if you entered the dialog by
single click you also expect the 'go back' button to work by
single click too.
The subdialog is a GtkListBox configured to be double click,
because it has an 'Accept' header bar button and we don't
really want to activate the subdialog items by single click,
but the 'go back' row is special and as explained before it is
expected to work by single click too.
So this commit adds the required single click handler for the
'go back' rows created in CCInputChooser.
Fixes#1954
The current layout intersection algorithm compares pointers to strings.
It assumes that `gnome_xkb_info_get_layouts_for_country()` and
`gnome_xkb_info_get_layouts_for_language()` will return two GList
containing pointers to the same strings. Looking at libgnome-desktop[1]
it seems like this is the case: given the same layout, the same pointer
to the layout id will be stored in both lists. However, this is an
implementation detail and we should not rely on that.
Rewrite the intersection algorithm in order to compare the strings. While
at it, use a more efficient algorithm: add all the items of the first list
to a set, then iterate over the second list and check if the item is in
the set. If this happens, remove the item from the set and add it to the
intersection list.
Probably the layout lists are not big enough to notice the difference, but
the complexity goes from O(N*M) to O(N+M).
[1] 3c8834af09/libgnome-desktop/gnome-xkb-info.c (L281)
country_layouts are being appended to the layouts_with_locale which results in less relevant
layout groupings. for example, we if choose Hindi language which is an Indian language,
all Indian language layouts are shown within it - including Tamil, Bangla etc.
furthermore, language_layouts are also getting appended for countries where they may not
belong, for example, English (Ireland) is shown when we search India.
The layouts_with_locale table is filled as union however it yields better
search results if we change that to intersection.
Relates #2114
GtkStyleContext will be deprecated in gtk 4.10.
https://docs.gtk.org/gtk4/class.StyleContext.html
This preserves code blocks where additional GtkStyleContext operations
were used, such as gtk_style_context_save/restore.
