Some characters in the scrollback buffer can appear in reverse video. But after scrolling again, they appear as normal, even when there was no output. This occurred while I was upgrading packages with apt on a remote machine (via ssh in xterm), perhaps due to the progress bar, which uses reverse video. But this was still occurring after the upgrade terminated (so there was no output at this time).
so... a) is this something that you can reproduce? b) were the characters in the scrollback supposed to be reversed, and then incorrectly reset? c) is this with bitmap fonts, or TrueType? d) there's no screenshot or other clue to see how to proceed. Comparing with #392, I suppose it's possible that there's an inconsistency in drawing/redrawing for some format-effector code, etc., but without some details on how to reproduce it, not much can be done.
so... a) is this something that you can reproduce? b) were the characters in the scrollback supposed to be reversed, and then incorrectly reset? c) is this with bitmap fonts, or TrueType? d) there's no screenshot or other clue to see how to proceed. Comparing with #392, I suppose it's possible that there's an inconsistency in drawing/redrawing for some format-effector code, etc., but without some details on how to reproduce it, not much can be done.
No, but after thinking about it, I now suppose that what occurred is the following issue, which I can reproduce with apt install --reinstall linux-image-6.1.0-18-amd64 linux-headers-6.1.0-18-amd64 (which recompiles the drivers, so generates some output). It is possible that I had selected some text, so that this text was in reverse video, then I forgot about it. But when there is output, some other part of the text becomes in reverse video, hence my surprise about random text being in reverse video when I was scrolling backward. I can reproduce that. It seems that this happens as soon as the selection reaches the scrollback buffer. Note that the range of columns of the part in reverse video remains the same, and despite the change of the text in reverse video, the selection remains the same when I paste it. Unfortunately, I can't reproduce the issue with a simple testcase. The reverse video disappeared. But if this is the above issue with the selection, the selection automatically disappears just by clicking in the xterm, which I might have done. Vector fonts, so TrueType? But I can reproduce the above selection issue with bitmap fonts too. The above command should give a hint.
The issue might be due to the progress bar, which is kept at the bottom of the xterm window while there is scrolling output above it. This probably involves some special technique (margins?) that could confuse xterm for the tracking of the selected text. Just a supposition... This is reproducible with the attached tty session in a 80x60 xterm, to be played by "xterm -e ttyplay ttyrecord". Just double-click on "Summary:", and scroll backward and forward...