Hi,

I've narrowed it down to the addition to frame in the glyph comparison. As far as I can tell, the attached patch removes the flickering for me. I saw the cursor blink once, but I couldn't reproduce that and I couldn't get it to do it again.

The patch is not suitable for applying to master as it certainly breaks something int he tty child frame code, but hopefully it gives you an idea of what the problem might be. I'm going to experiment with accounting for the NULL frame in the space glyph and see if that helps.

Aaron

On Sun, Mar 16, 2025 at 2:00 AM, Gerd Möllmann <gerd.moellmann@gmail.com> wrote:

Aaron Jensen <aaronjensen@gmail.com> writes:
One other thing, it may be related to tab-bar mode. It seems to be connected to when I switch tabs — one tab has a vterm buffer scrolling output and the other just has a grep output, for example. If I don't get the flicker in the grep output, I can switch back and forth between the two tabs a couple times and I'll start to get it.
Doesn't ring a bell, I'm afraid. Tab bar, AFAIU it, is "just playing with window configurations". Why that would lead to flickering, I can't imagine ATM.