How to force redraw when returning to command line from command line history window?

Question

Something that's bothered me for about a decade now is that when I switch from command line into the command-line-history window (by pressing <c-f>) and then switch back (by pressing <c-c>), the command line history window remains visible. I noticed that if I force a refresh by changing the size of the gVim window then the history window goes away so I think it just needs a redraw. Is there a way to force a redraw to occur when hitting <c-c>?

Answer 1

Try this autocmd:

augroup my_cmdline_window
    au!
    au CmdWinEnter * nno  <buffer><expr><nowait>  <c-c>  '<c-c>'.timer_start(0, {-> execute('redraw')})[-1]
augroup END

The timer is necessary to delay :redraw. Without it, :redraw would be executed before C-c is pressed, that is before the command line window is left, which is too soon. Vim needs to redraw the screen after the command line window has been left.

For more information, see:

:h CmdWinEnter
:h map-<buffer>
:h map-<expr>
:h map-<nowait>
:h timer_start()
:h lambda
:h execute()
:h :redraw