Currently, when a button in my app has the focus (i.e. will trigger with RETURN), it has a tiny tiny highlight around the perimeter of the button, that is very hard to see. I would like to make this more obvious either by:
making the perimeter highlight bigger/brighter
or
by coloring the default button.
I have tried the code below, but since it does not work, I may be barking up the wrong tree.
Thanks for that suggestion. I suspect that that is a GTK4 call as I am using GTK3+ at the moment, and I get an undefined reference error. Is there a similar feature in GTK3+?