Keyboard naviagation in context menu: Left arrow key to move back only works on first entry
Context menus in libadwaita, as found in the Gnome Texteditor, change the view when clicking a sub-item. For going back to the super level list, you can click the title entry on the top, which is preceded by a "<" icon. For keyboard navigation, it works like a normal list entry: You can select this entry and hit "Enter" to go back.
On the title list entry – and only on this one – you can, however, also use the left arrow key to navigate back. This is very clever, as this is one very intuitive way of going back in such menus.
However, you can't use the left arrow key to go back if any other entry than the first one is highlighted. In long lists, being able to go back using the left arrow key with any entry highlighted would be extremely useful (for example: in Gnome Text Editor, there are about 120 languages available for spell checking; and the current one, not the title/back entry, is the selected one when entering the submenu).
The left arrow key not being available mid-list kind of defeats the purpose of this feature: On the first entry, you could as well press enter. In long submenus, when the top entry is not the one that is selected by default, undoing accidentally entering the submenu is extremely tedious.