How to use "FocusGained" to stop my cursor from moving

Question

I tend to use GVim a lot. Very frequently, I'll click on some other window and then when I click on vim to regain focus, my cursor will end up in some random location depending on where I clicked. I find this extremely obnoxious. I can generally remember where my cursor is before navigating away, but I don't like having to hunt it down every time I return to using gvim.

I thought I could fix this by adding this to my .vimrc:

au FocusGained * normal <C-o>

(where <C-o> is the actual control character) but this doesn't work. It usually just navigates away from my current file. This happens even if I add

au FocusLost * normal m`

too.

So I gave up on fixing this through the use of the jumplist. Instead, it seems like I could fix this by setting mouse. In general, I'd prefer to have

set mouse=a

I initially tried the following autocommands:

au FocusLost * set mouse=
au FocusGained * set mouse=a

But it seems like the autocommand is processed before the mouse click is registered and the cursor is moved.

My next thought is to asynchronously re-enable the mouse so that the mouse click will be ignored before my mouse setting is changed. Something along the lines of:

au FocusGained * async_call("set mouse=a", 200ms) "pseudocode

But I'm not sure exactly how to do this step. I can't find any info on the correct way to asynchronously call vimscript. I would like an answer either for how to do this asynchronously like I explained, but if there's a simpler way too achieve this then that would be appreciated too.

Any help would be appreciated. I am using vim 8.0 GUI version on Windows.

Answer 1

I guess mouse clicks don't update the jump list. (:help jump-motions seems to confirm this is the case.)

Try this, for the async solution:

augroup MouseHack
  autocmd!
  autocmd FocusLost * set mouse=
  autocmd FocusGained * call timer_start(200, 'ReenableMouse')
augroup END

function ReenableMouse(timer_id)
  set mouse=a
endfunction

Note that this requires the +timers feature, introduced in v7.4.1578. If you're likely to be running an earlier version of Vim, you'll want to surround all the above with a if has('timers') guard.

As of v8.2.3761, this will also work in terminal Vim.