Blank cursor when switching between X and Emacs window

[ipvych]

Trying out EXWM and when switching between windows point inside Emacs becomes blank. It sometimes resets on it's own after some activity or it just gets stuck with call to redraw-display fixing it. I can reproduce this without any installed packages with example config.

This issue is present in both master and ELPA build of exwm
Output of emacs-version: GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo version 1.16.0, Xaw3d scroll bars)
Output of Xorg -version:

X.Org X Server 1.21.1.8
X Protocol Version 11, Revision 0
Current Operating System: Linux nixos 6.4.7-zen1 #1-NixOS ZEN SMP PREEMPT_DYNAMIC Tue Jan  1 00:00:00 UTC 1980 x86_64
Kernel command line: <omitted>

Current version of pixman: 0.42.2
       Before reporting problems, check http://wiki.x.org
       to make sure that you have the latest version.

Here is the log where I switch between qutebrowser and scratch windows starting from focused scratch buffer where I marked cases where focus changed correctly by inserting --------------- marks - http://0x0.st/Hfp9.log (github does not allow uploading full log, if the paste expires please notify me and I will reupload it)

[ipvych]

Adding delay after switching window like so

(defun ipv-exwm-other-window ()
  "Call `other-window' interactively with workaround for EXWM to not lose focus."
  (interactive)
  (if (not exwm-window-type)
      (call-interactively #'other-window)
    (call-interactively #'other-window)
    (sleep-for 0.02)))

seems to be a working workaround for this.

[medranocalvo]

I could not reproduce with a minimal config:

(push "/path/to/xelb" load-path)
(push "/path/to/exwm" load-path)
(require 'exwm)
(exwm-input-set-key (kbd "s-o") 'other-window)
(exwm-init)
;; C-x 3
;; M-x async-shell-command RET xterm RET
;; s-o
;; s-o ...

Could you try the above? The issue might lie in the example config, which I did not test.

[ipvych]

Reproduced it with your config.

My ~/.xinitrc

exec emacs -Q -l ~/test.el

Where ~/test.el is

(push "<homedir>/.config/emacs/elpa/xelb/" load-path)
(push "<homedir>/.config/emacs/elpa/exwm/" load-path)
(require 'exwm)
(exwm-input-set-key (kbd "s-o") 'other-window)
(exwm-init)

Tried starting in separate tty with my current WM running, in tty1 without any other wm running both as command in .zprofile and just by running either startx or exec startx. I have second monitor and tried without it as well, could reproduce it in all cases.

[tazjin]

I can reproduce this, too, with my normal config and a minimal one. In my case, switching to a different workspace on the same monitor and back fixes it (which is similar to my workaround for the bug where Chromium doesn't get input focus).

[medranocalvo]

Hm.

Please post the output of (emacs-build-description) (remove sensitive information if any). I'm building without X toolkit, will try to match your build.

Please use git bisect to try to find out which commit introduces the issue.

Thank you both.

[ipvych]

Output of (emacs-build-description)

In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo version
1.16.0, Xaw3d scroll bars)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: NixOS 23.11 (Tapir)

Configured using:
 'configure --prefix=/nix/store/81g0rphgaisjz1kf6mfdlqv9m69kjfkf-emacs-29.1
 --disable-build-details --with-modules --with-x-toolkit=lucid --with-xft
 --with-cairo --with-native-compilation --with-tree-sitter --with-xinput2'

I am trying EXWM for first time and I had this issue from beginning so can't help with bisect. Only thing that might be helpful is that this issue is present in both ELPA version and master branch.

[tazjin]

and for me it's:

In GNU Emacs 29.1 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
version 1.16.0, Xaw3d scroll bars)
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: NixOS 23.11 (Tapir)

Configured using:
 'configure
 --prefix=/nix/store/crk4w3rpf8mwmf2f031s934za4rz2dva-emacs-29.1
 --disable-build-details --with-modules --with-x-toolkit=lucid
 --with-xft --with-cairo --with-native-compilation --with-tree-sitter
 --with-xinput2'

Note that if you have Nix installed you can get my exact Emacs (including EXWM config) by running nix-build -E '(import (builtins.fetchGit "https://cl.tvl.fyi/depot.git") {}).users.tazjin.emacs' (though it might take a while).

[medranocalvo]

Still could not reproduce under macOS. I'll try to set up a Linux machine.

@ipvych, that's regrettable. Thank you for taking the time to report the issue.

[... time passes ...]

Set up an Ubuntu 22 machine. Performed the following steps:

 sudo apt update
 sudo apt upgrade
 sudo reboot
 sudo apt install xfce4
 sudo apt install build-essential 
 sudo apt autoremove 
 git clone https://git.savannah.gnu.org/git/emacs.git
 cd emacs/
 git checkout emacs-29.1
 ./autogen.sh 
 sudo apt install autotools-dev libtree-sitter
 sudo apt build-dep emacs
 sudoedit /etc/apt/sources.list
 sudo apt update 
 sudo apt build-dep emacs
 gcc --version
 sudo apt install libgccjit-11-dev 
 sudo apt install libtree-sitter-dev 
 ./autogen.sh 
 ./configure --prefix=$PWD/rel --with-modules --with-x-toolkit=lucid --with-xft --with-cairo --with-native-compilation --with-tree-sitter --with-xinput2
 make -j8
 make install
 man startx
 echo '$HOME/emacs/rel/bin/emacs' >~/.xinitrc
 startx

Note that the .xinitrc contains a call to bare Emacs, no EXWM (plan was to install EXWM from GNU ELPA). Emacs' cursor appears hollow, as you describe. Remember: no EXWM.

Rebuilt --without-xinput2: the cursor is now back to normal.

Seems an Emacs issue. Reminds me of #899... Tried setting x-no-window-manager with a --with-xinput2 build:

$HOME/emacs/rel/bin/emacs --eval '(setq x-no-window-manager t)'

No dice.

Noticed that opening and closing a menu bar menu (e.g. "File") changes the cursor to full.

Summary:

• Cursor is hollow when starting Emacs without window manager.
• Setting x-no-window-manager does not help.
• Clicking menu bar item fixes the cursor.
• Building with --without-xinput2 fixes the issue.
• EXWM not related: was not installed (though there might be separate EXWM issues, see Show tab-line when tab-line-mode is enabled #899)

Please, report this to Emacs (post a link to the bug tracker in this ticket).

As for EXWM, you can work-around this by building Emacs --without-xinput2.

[ipvych]

What building with or without xinput changes is whether emacs cursor is blank or not on startup when cursor is hovering over emacs window, it does not resolve issue with cursor becoming blank when switching windows in EXWM.

What is working for me is setting x-no-window-manager to t. It does not change whether cursor get focus on startup with plain Emacs, but in EXWM it fixes the issue with losing focus when switching windows. Thanks, I did not know that variable existed! Maybe it should be documented in the wiki?

I also tried Emacs 28 and it both has no issues with plain emacs cursor focus on startup (which I think is expected since it does not use xinput) and EXWM also works just fine without even setting x-no-window-manager, maybe latter should be reported as issue since I would expect emacs 29 build without xinput to work the same as emacs 28 without having to set this variable so something might have broken there.