Some widgets in .ui files do not set visible property - this is changing default value in GTK+ 4
GTK+ 4 changes the default value of the visible widget property from FALSE to TRUE. Thus any widget without the visible property explicitly set to False in GtkBuilder files will become visible on migration to GTK+ 4. We need to add these in where they are missing.
Note that after migration we ca remove all the visible properties set to True if desired.