There could perhaps be some text indicating that the different keys do in different part of the widget UI's menu system. Typically, something at the bottom of each menu along the lines of:
Space: Select, Enter: Save, Esc: Cancel
Another annoyance is that pressing 'space' on a submenu entry does absolutely nothing... this has then caused my to switch to pressing 'enter', at which point, I will then go into the menu, use up/down to select the setting that I want to change, and then press enter again, only to find that this takes me straight out of the menu system without changing anything, Worse still, it exits the menu system entirely, rather than just going up one level. This can also be annoying when wanting to change more than one option at a time. It might be an option to take the user back to the top-level menu, instead. or to prompt on exiting any given menu with changes saved.
I would try to use the shortcut keys, but the lettering is not always obvious, and the dark blue that is used is hard to see against the black, especially when using a 1x1 on a reasonably high resolution display. There may be room for improvement here. Now that I look at it, the GTK+ UI's practice of placing tickboxes to the left of the option name seems a far better way of doing things, too.
The confirmation dialogue for widget just says 'Fuse - Confirm - Yes/No' whereas the ones for the GTK+ UI give a little more information (although the hard reset dialogue should specifically mention that it's a hard reset).