That is how Thunderbird selects text. Is there some point other than it is different to a word processor.

Thanks for your response.

Maybe from the example I gave you could perhaps infer where the cursor is, but there are times when I select a few empty lines, perhaps to delete them, but there is no indication of highlighting, and the cursor disappears. I usually have to unselect and do the selection again to make sure I am about to do what I intend.

Every other editor I have used (including the one I am writing this reply with) shows selected empty lines, and most show the cursor because it is also useful information, though less so than the invisible blank lines.

I did look through the code base, and given the quality of it, it seems rather incongruous that it would implement such an unusual UX for such a common operation.

I love DXR for perusing code on line, by the way.

I suppose I could try to set up a build environment, and perhaps find and suggest a 'fix'. I assume there is a debugging environment in Linux - Eclipse, perhaps?