The RenameFolderMenu uses the internal box as a menu item, while PopupMenu
expects to have PopupBaseMenuItem based children with a delegate set.
Instead of using a custom menu with a customized box acting as menu
item,just add a RenameFolderMenuItem that inherits from the parent,
adjusting the features as we need them. In fact, the rename folder menu item
doesn't need any label, padding or default styling so we can reuse
PopupMenuBaseItem after we use our styling properties and we set the
Ornament to HIDDEN.
To get the proper style in place, define rename-folder-popup and
rename-folder-popup-item to override the default popup-menu-item rule
padding instead of using margins.
Pass the menu item as menu's focusActor as this will key-focus it on pop-up,
by overriding the key_focus_in() vfunc we can then delegate the focus
handling to the entry's clutter-text.
Also override the map() vfunc in order to update the entry's content before
mapping the entry.
Finally, use the item's activate method in order to tell the parent menu
we're done with it and that the menu can be closed.
As consequence we can also remove the menu's popup() method, and just use
the default open().
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/720
dab60d5580