[KevinH]

The point we are trying to make is to then use "open with" with emacs or whatever editor does things the way you want.

Using the keyboard predominantly is fine (BetterRed does that) but having different widgets fighting for focus is not. And there are some things that a mouse or mouse pad are better at including selecting specific but widely separated files in BookBrowser.

If you can program, then modify your own copy of Sigil to do what you want. BeckyEbook does that and adds menus and features she needs or wants.

Our goal is to make Sigil work like most users want (myself included) who do not want to memorize more than a handful of useful key sequences and rely on the menus and toolbar icons for all others.