I am running into an issue on both windows and linux with the newer gdl/gdlmm releases since 3.38 where docks no longer have grips and throw a new assertion which never before happened back when things were working.
Upon running show_all on a newly created dock I get this…
Then the dock appears and can be iconified but not dragged and the entire toolbar is blank where the label text used to be.
I have a debug build of gdl and gdlmm where I am working this and it seems gdl_dock_item_grip_realize() hits an assert where grip->priv->label is null and the code path was expecting it not to be.
I get no other gtk warnings before that. If I backdate gdl the issue goes away thus I am confused what is going on. Can trace in lldb just not sure why or what is going on.
Oddly if I manually create a new gtk::label, then get the dockItems grip using get_grip() then set_label() I can get the dock grip to appear again (still no label visible) but I can drag it.
Upon doing anything though the assertion comes back and the behavior with the grip triggers again and no dragging is possible. If I create two dock windows something causes the first to call realize() again and it ruins the fix and dumps the warning again the console.
I am still investigating but it seems something is happening when unrealized that trashes the label when realize is expecting it not to be?