@ kovid
I have a few suggestions regarding Calibre Edit Book. Don't know how hard it is to implement them, but would kindly ask you to consider:
1) adding "Split at Cursor" option in code view (possibly via right click or a keyboard shortcut - Sigil used CTRL+Space). It would give more control and be more precise than the existing green-line solution;
2) adding "Minimal Match" for RegEx searches next to "Wrap" in search mode;
3) adding the buttons and/or keyboard shortcuts to change lettercase: lowercase, uppercase, capitalize headline-style, capitalize sentence-style; this was mentioned earlier, don't know if you're working on it or not.
Thank you for all your hard work