[vim/vim] vim is flickering during scroll (Issue #18972)
charan
chrnz008 created an issue (vim/vim#18972)Steps to reproduce
ctrl - f
Expected behaviour
vim is flickering when scrolled using ctrl-f
i tried using vim -u NONE still same issue
Version of Vim
VIM - Vi IMproved 9.1 (2024 Jan 02, compiled Dec 15 2025 22:16:40) MS-Windows 64-bit GUI/console version with OLE support Included patches: 1-1984
Environment
OS: Windows 11
Terminal: alacritty
shell: nushell
Logs and stack traces
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Mateo Gjika
mateoxh left a comment (vim/vim#18972)Try let &t_ut=''
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charan
chrnz008 left a comment (vim/vim#18972)@mateoxh i ve tried it seems to have no effect
and i actually found that set ttyscroll=3 seems to work
but the cursor is still flickering when there is a long press
https://github.com/user-attachments/assets/594256c8-904f-424e-ba30-4e0ac09e9f19
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Mateo Gjika
mateoxh left a comment (vim/vim#18972)Does it happen with other terminal emulators?
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charan
chrnz008 left a comment (vim/vim#18972)Does it happen with other terminal emulators?
yes , it is happening with windows terminal and wezterm too!!
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dezza
dezza left a comment (vim/vim#18972)Have you tried a regular bash as starting shell, newer builds? tried building your own build with minimal features?
Regarding last video is it the cursor blinking you mean? I do see the full redraw flickering in first video, but I've never encountered this in terminal vim - I think its more likely to be another layer.
Try with windows terminal or mintty which both have different backends iirc, be sure to test just bash.
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charan
chrnz008 left a comment (vim/vim#18972)Have you tried a regular bash as starting shell, newer builds? tried building your own build with minimal features?
Regarding last video is it the cursor blinking you mean? I do see the full redraw flickering in first video, but I've never encountered this in terminal vim - I think its more likely to be another layer.
Try with windows terminal or mintty which both have different backends iirc, be sure to test just bash.
i've already tried all of them (except custom builds) it is not a shell or terminal issue
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dezza
dezza left a comment (vim/vim#18972)i've already tried all of them (except custom builds) it is not a shell or terminal issue
Then someone on same OS must be able to reproduce.
Can you? On a different machine?
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charan
chrnz008 left a comment (vim/vim#18972)@dezza well i don't have another windows machine
i just install vim.vim using winget
and here is my config (i dont do anything with my os except mapping caps to ctrl)
vimrc
the issue is not occurring in neovim or vim on wsl
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dezza
dezza left a comment (vim/vim#18972)I believe winget installs it in some kind of sandbox, but its a long time since I tried it. You could try to look into it.
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charan
chrnz008 left a comment (vim/vim#18972)Update :
ive tried it in another windows 11 machine i can still see the statusline flicker with ctrl-f
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dezza
dezza left a comment (vim/vim#18972)did you try regular installer https://github.com/vim/vim-win32-installer/releases/download/v9.2.0033/gvim_9.2.0033_x64.exe
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charan
chrnz008 left a comment (vim/vim#18972)@dezza yes there is no difference (and sometimes vim.exe is not getting registered to path if i use regular installer)
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mattn
mattn left a comment (vim/vim#18972)Which plugins do you use?
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charan
chrnz008 left a comment (vim/vim#18972)Plug 'Konfekt/filepicker.vim' "use yazi as a file manager Plug 'christoomey/vim-tmux-navigator' Plug 'chrnz008/gruber.vim' "colorscheme Plug 'chrnz008/schizo.vim' "utilities Plug 'jiangmiao/auto-pairs' Plug 'tpope/vim-surround'
the issue is reproducible even without config
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charan
chrnz008 left a comment (vim/vim#18972)@mattn update!! the issue is not appearing when im splitting windows
https://github.com/user-attachments/assets/d6af81ae-2f74-4d03-bea5-05797127ea5a
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dezza
dezza left a comment (vim/vim#18972)Try maximizing the window as much as possible (so 1 line is left for the others).
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charan
chrnz008 left a comment (vim/vim#18972)Try maximizing the window as much as possible (so 1 line is left for the others).
I'm sorry i did not understand what do you mean
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dezza
dezza left a comment (vim/vim#18972):split
:vsplit
:botright resize 99
:vert resize 99
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mattn
mattn left a comment (vim/vim#18972)The flicker is caused by screenclear() in win_do_lines() (screen.c). When the scroll amount is large (Rows - line_count < 5) and the window spans the full width, screenclear() clears the entire terminal screen before redrawing all lines. The blank screen is visible as flicker. This is why the flickering occurs during scrolling.
With a vertical split, wp->w_width != topframe->fr_width, so this condition (screen.c:3803) is skipped and the scroll region path is used instead, which shifts content in-place without blanking.
The fix is to replace screenclear() with redraw_as_cleared(). screenclear() both invalidates the internal ScreenLines[] buffer and sends T_CL to clear the terminal. redraw_as_cleared() only invalidates the buffer. Since this path returns FAIL, the caller redraws all lines via win_line() which overwrites each character in place, so the screen is never blank.
diff --git a/src/screen.c b/src/screen.c index 48261009f..921399163 100644 --- a/src/screen.c +++ b/src/screen.c @@ -3804,7 +3804,7 @@ win_do_lines( && wp->w_width == topframe->fr_width) { if (!no_win_do_lines_ins) - screenclear(); // will set wp->w_lines_valid to 0 + redraw_as_cleared(); // don't clear the screen to avoid flicker return FAIL; }
Could you please try this patch?
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charan
chrnz008 left a comment (vim/vim#18972)@mattn the scroll issue is resolved but the cursor is still flickering
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mattn
mattn left a comment (vim/vim#18972)I tried Alacritty for a while, and it doesn't seem to render split windows correctly in the first place. Could you try reproducing this issue on a different terminal emulator (e.g. Windows Terminal, WezTerm) to rule out an Alacritty-specific rendering problem?
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charan
chrnz008 left a comment (vim/vim#18972)@mattn I've tried both windows terminal and wezterm the issue still persists even though it is minute compared to alacritty.
- idk if this helps to resolve the issue
but when i hold esc key in vim this happens
https://github.com/user-attachments/assets/2fd7f0ab-f5f8-45f8-9bd3-4477ed28214f
Neovim doesnt do this
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mattn
mattn left a comment (vim/vim#18972)@chrnz008 Could you share more details so we can reproduce the cursor flickering?
- Which version of Vim are you using? (output of
vim --version | head -3) - Which terminal emulator and version? (e.g. Windows Terminal 1.x, WezTerm 2024xxxx)
- What is your
$TERMvalue? (echo $TERM) - Are you running Vim natively on Windows (win32) or through WSL?
- Minimal steps to reproduce:
vim -u NONE- Hold ESC key
- Cursor flickers?
- Does
set novisualbellorset t_vb=make any difference? - What is your cursor style setting? (
set guicursor?orset t_SI? t_EI? t_SR?)
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charan
chrnz008 left a comment (vim/vim#18972)- version : VIM - Vi IMproved 9.2 (2026 Feb 14, compiled Apr 8 2026 22:37:06)
MS-Windows 64-bit GUI/console version with OLE support
- Included patches: 1-323
- Microsoft.WindowsTerminal 1.24.10921.0
echo $TERM: screen-256color- native windows 11
Minimal steps to reproduce:
Hold ESC key
Cursor flickers?
above steps
but vim -u NONE has no issue but it is there with after set nocp(with vim -u NONE) or vim --clean
6. no
7. a:block-blinkon0 but the issue does occur without defaults too
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mattn
mattn left a comment (vim/vim#18972)This is expected behavior. When 'compatible' is off (which happens automatically when a vimrc exists), 'ttimeout' is turned on. This means Vim waits for 'ttimeoutlen' milliseconds after ESC to check if it's part of a key code sequence (e.g. <Esc>[A for arrow keys). If 'ttimeoutlen' is -1 (the default), it falls back to 'timeoutlen' (1000ms), which causes a noticeable delay and cursor redraw on each ESC press.
Try adding this to your vimrc:
set timeout set ttimeoutlen=100
This may help reduce the flickering.
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mattn
mattn left a comment (vim/vim#18972)Note that vim --clean loads defaults.vim, which sets ttimeoutlen=100. With this short timeout, the flickering should not be noticeable. Could you double-check whether the issue actually reproduces with vim --clean?
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charan
chrnz008 left a comment (vim/vim#18972)Note that
vim --cleanloadsdefaults.vim, which setsttimeoutlen=100. With this short timeout, the flickering should not be noticeable. Could you double-check whether the issue actually reproduces withvim --clean?
yes it does
Try adding this to your vimrc:
set timeout
set ttimeoutlen=100
this isn't solving the issue
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mattn
mattn left a comment (vim/vim#18972)@chrnz008 I confirmed that the cursor flickering does not reproduce with vim --clean on my end (i.e., when defaults.vim is loaded). However, I'm unable to reproduce the issue on my machine at all, so I need your help to narrow it down.
Could you please bisect which part of defaults.vim is responsible? Copy sections from defaults.vim (located at $VIMRUNTIME/defaults.vim) into your vimrc piece by piece and test after each addition. For example:
-
Start with just this in your vimrc and test:
set nocompatible set ttimeout set ttimeoutlen=100
-
If that doesn't fix it, add more settings from defaults.vim one by one (e.g.
set display=truncate,set scrolloff=5,set mouse=a,syntax on,filetype plugin indent on, etc.) and test after each addition. -
Report back which specific line(s) make the flickering go away (or not).
This will help us understand whether the issue is related to a specific option or a combination of settings. Thank you!
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charan
chrnz008 left a comment (vim/vim#18972)@mattn the issue starting from line 23 in defaults.vim
" Use Vim settings, rather than Vi settings (much better!). " This must be first, because it changes other options as a side effect. " Avoid side effects when it was already reset. if &compatible set nocompatible endif
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mattn
mattn left a comment (vim/vim#18972)@chrnz008 Sorry, my previous comment was unclear. Let me clarify what I'd like you to try.
We already know that set nocompatible changes behavior — that's expected. The key observation is that vim --clean does not reproduce the flickering on my end, which means some other setting in defaults.vim is preventing it.
So what I'd like you to do is:
- Create a minimal vimrc with just
set nocompatible(which reproduces the flicker for you). - Then add the other settings from
defaults.vimone by one and test after each addition:set nocompatible " add one of these at a time and test: set ttimeout set ttimeoutlen=100 set display=truncate set scrolloff=5 set nrformats-=octal
- Find which setting makes the flickering stop (i.e., matches
--cleanbehavior).
This will help us identify the specific option that fixes the issue. Thank you!
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charan
chrnz008 left a comment (vim/vim#18972)@mattn i've tried as you said but there is no effect.
The key observation is that
vim --cleandoes not reproduce the flickering on my end, which means some other setting indefaults.vimis preventing it.
well i tested vim in another computer (win11) and had the same issue
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mattn
mattn left a comment (vim/vim#18972)@chrnz008 If your vimrc doesn't use a plugin manager or anything that modifies runtimepath/packpath, then copying the entire contents of defaults.vim into your vimrc should produce the same behavior as --clean.
Please try the following:
- Back up your current vimrc first.
- Replace your vimrc with the entire contents of
$VIMRUNTIME/defaults.vim. - Confirm that the flickering stops (it should behave the same as
--clean). - Once confirmed, remove settings one by one to find which removal causes the flickering to return.
If the flickering does NOT stop at step 3, please share your full vimrc.
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charan
chrnz008 left a comment (vim/vim#18972)3. Confirm that the flickering stops (it should behave the same as `--clean`).
just to clarify vim --clean still produce the flicker for me
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charan
chrnz008 left a comment (vim/vim#18972)@mattn im not lying !! having wezterm on my system doesnt produce the vim flicker issue alacritty
but it does flicker when i uninstalled it and restarted . i tried several times by restarting without removing the flicker isn't produced !!
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charan
chrnz008 left a comment (vim/vim#18972)@mattn should i open a new issue (i've tested the above procedure multiple times)
here are the steps to reproduce:
- launch vim in alacritty (flicker should occur)
- install wezterm and launch vim in it
- try to use vim in alacritty the flicker is not produced.
(i could screen record if you want) - to reset the flicker behaviour uninstall wezterm and restart
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charan
chrnz008 left a comment (vim/vim#18972)closing this because it is not consistent across other terminal emulators
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jclsn
jclsn left a comment (vim/vim#18972)@chrnz008 Did you try Windows Terminal? I had issues with it as well
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charan
chrnz008 left a comment (vim/vim#18972)@chrnz008 Did you try Windows Terminal? I had issues with it as well
@jclsn the cursor flicker only happens with alacritty as far as i know
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