@signum - thanks for all the comments - just what we were looking for (well, hoping there wasn't anything but of course there's always something
1) I'll fix those entities. As for others, well that's just an Example list. You're supposed to create your own, copy those, use them, ignore them. I'll add some, but its got the basics in it so people know what can be done. Though if someone wants to post a larger list to use, please do
2) ctrl-shift-return works for me on Ubuntu. Did you override the default keyboard shortcut? Is something in KDE catching it? Try changing Insert Split Marker to another shortcut and see if it works
3) Ah, zero length file - we'll look at it. EDIT: longstanding issue that won't be fixed anytime soon. Sigil assumes you have a valid EPUB to start. EDIT - seems KDE related issue, will try Qt file dialog instead of native.
4) KDE and multi-select in Sigil or Qt don't get on. I tried KDE but had to leave it because of this.
5) We'll retest on the regex search issue, but those types of issues were addressed - maybe they came back. Without a specific test it is hard to track though.
6) Save as sounds quite unusual so we'll test that. EDIT - seems fine on Ubuntu and Windows. What exact scenario can be used to reproduce this?