Window resizing by setting columns and rows doesn't properly redraw it

[eirnym]

[GUI only]
When vim :set command resizes a window by setting columns and rows directly, MacVim doesn't redraw window with background color set.

Issue is reproducable in all builds at least after 122 and not connected with recent guioptions changes. Earlier don't want to open on my machine and I don't want to investigate reasons. As far as I remember, some earlier builds had no this issue.

Minimal list of commands to reproduce feature on (dark background is for contrast):

colo darkblue
setlocal columns=85

A quick demonstration with opeining Python file:

Minimal .vimrc for this demonstration is:

fun! PythonSetup()
    setlocal ts=4 sts=4 sw=4 nu
    setlocal colorcolumn=79
    if has('gui_running')
        setlocal columns=85
    endif
endfun

autocmd FileType python call PythonSetup()

[eirnym]

A while ago I had setting columns for python files in general, but when I've started to work with terminal it started just cut a window if it shorter. Probably, the part of the issue could be inside Vim core itself, but we should check our side first.

[eirnym]

BTW, it could be source of a few issues related to window resizing including moving it to an another screen

[eirnym]

set MMUseCGLayerAlways to NO hides this issue.

in the (#557 (comment)) people recommend the opposite

[eirnym]

The workaround is to add to your vimrc following line:

autocmd VimResized * redraw!

[ychin]

I'm closing this issue. It only manifests itself when MMUseCGLayerAlways is set, and there should be no reason for this to be set anymore since all relevant rendering bugs in the default renderers are fixed.

Rendering and window behaviors should work properly by default without any secret undocumented settings in all supported OS versions, and you should consider the MMUseCGLayerAlways setting to be deprecated and will be removed in future. If you encounter other resizing and rendering issues without this flag, please file an issue for those separately.