Skipping intermediate draws while autorepeating down-arrow in emacs
Performance issue
Thanks for filing an issue! Please answer the questions below so I can help you.
- iTerm2 version: 3.5.14
- OS version: MacOS Tahoe 26.0
- Attach a debug log, if possible.
- Attach a screen capture video if it would make the reproduction steps clearer.
- Please attach a process sample
iTerm2_2025-09-22_190923_FNRs.sample.txt
PLEASE ATTACH YOUR PLIST FILE FOR BUG REPORTS! Seriously! I'll probably ask you for it if you don’t.
Detailed steps to reproduce the problem
- Set local Mac's keyboard autorepeat rate to maximum
- ssh to a remote host on a LAN (wifi connection)
- Open a reasonably large Perl source file in GNU Emacs 30.1
- Hold down the down-arrow (mapped to ).
What happened
The cursor, instead of hopping down line by line, stays in one place as the keystrokes are apparently buffered. On releasing the key, the display is updated to show the cursor at its final position.
What should have happened
It should have updated the display to show the cursor moving, thus providing feedback.
With everything else being equal, running this scenario on Terminal behaves properly. So it's unlikely to be related strictly to network delays. Moreover, I see that the same bad behavior is happening when I edit a local file.
I feel like this behavior really surfaced when upgrading to Tahoe.