Host cursor disappears over certain host applications on second monitor when LG is used

[kutukvpavel]

Hi!
I've been stuck with this peculiar mouse cursor issue ever since I started using LG, around 1.5 years ago. It's not critical, but it is super annoying.

Affected host system information

OS: Debian Linux 11 and 12 (including w/bpo)
Kernel: 5.9.x-6.11.x, currently 6.11.10-amd64
DE: Gnome 42 and 43, currently 43.9
WM: Wayland
LG version: B6, B7-rc1
Monitor setup: desktop extended to the second monitor on the right

Guest

Win11

The bug

When looking-glass-client is started, host mouse cursor starts to consistently disappear over maximized windows of certain applications, if they are placed on the secondary monitor. The list of affected applications used to include Firefox, Nautilus and various apps run under Wine, and some others. A recent (several month ago) update fixed it for Firefox, though I'm not sure whether it was a Firefox update or a system update that did it.

I believe in the past this didn't happen if LG client had itself been run on the secondary monitor, but I'm unable to do so altogether any more (it is always placed on the main monitor when run).

The worst part of this behavior is: it is persistent even after LG client is closed.

Minimal repro

Log in, open Nautilus and maximize it on the secondary monitor. Then run looking-glass-client on the main monitor by any means. Move the mouse over Nautilus window, and the cursor will be invisible over it. Close the LG client window. Mouse cursor is still invisible over Nautilus.

LG config

/etc/looking-glass-client.ini

[win]
fullScreen=yes
borderless=no

[spice]
alwaysShowCursor=yes

LG logs

00:00:00.000 [I]              main.c:1859 | main                           | Looking Glass (B7-rc1)
00:00:00.000 [I]              main.c:1860 | main                           | Locking Method: Atomic
00:00:00.000 [I]           cpuinfo.c:38   | cpuInfo_log                    | CPU Model: AMD Ryzen 7 5700X 8-Core Processor
00:00:00.000 [I]           cpuinfo.c:39   | cpuInfo_log                    | CPU: 1 sockets, 8 cores, 16 threads
00:00:00.019 [I]            config.c:566  | config_load                    | Loading config from: /etc/looking-glass-client.ini
00:00:00.038 [I]              main.c:1185 | lg_run                         | Using font: /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
00:00:00.038 [I]           ivshmem.c:128  | ivshmemOpenDev                 | KVMFR Device     : /dev/shm/looking-glass
00:00:00.041 [I]             audio.c:159  | audio_init                     | Using AudioDev: PipeWire
00:00:00.041 [I]                ps.c:245  | purespice_connect              | Connecting to socket 127.0.0.1:5900
00:00:00.051 [I]               rsa.c:178  | rsa_encryptPassword            | Using Nettle
00:00:00.052 [I]                ps.c:268  | purespice_connect              | Connected
00:00:00.052 [I]             agent.c:103  | agent_connect                  | Connected to the spice guest agent
00:00:00.052 [I]      channel_main.c:167  | onMessage_mainName             | Guest name: win11
00:00:00.052 [I]      channel_main.c:183  | onMessage_mainUUID             | Guest UUID: c27c4b08-9a3e-4743-8823-d47eac2848c6
00:00:00.063 [I]                ps.c:644  | ps_connectChannel              | INPUTS channel connected
00:00:00.063 [I]           channel.c:323  | onMessage_notify               | [notify] keyboard channel is insecure
00:00:00.063 [I]               egl.c:289  | egl_initialize                 | Double buffering is off
00:00:00.063 [I]              main.c:1139 | tryRenderer                    | Using Renderer: EGL
00:00:00.063 [I]           wayland.c:120  | waylandInit                    | Compositor: gnome-shell
00:00:00.063 [I]           wayland.c:130  | waylandInit                    | Selected  : xdg
00:00:00.063 [W]              idle.c:31   | waylandIdleInit                | zwp_idle_inhibit_manager_v1 not exported by compositor, will not be able to suppress idle states
00:00:00.075 [I]                gl.c:58   | waylandGetEGLDisplay           | Using eglGetPlatformDisplay
00:00:00.094 [I]               egl.c:856  | egl_renderStartup              | Single buffer mode
00:00:00.096 [I]               egl.c:883  | egl_renderStartup              | EGL     : 1.5
00:00:00.096 [I]               egl.c:884  | egl_renderStartup              | Vendor  : AMD
00:00:00.096 [I]               egl.c:885  | egl_renderStartup              | Renderer: AMD Radeon RX 580 Series (radeonsi, polaris10, LLVM 15.0.6, DRM 3.59, 6.11.10+bpo-amd64)
00:00:00.096 [I]               egl.c:886  | egl_renderStartup              | Version : OpenGL ES 3.2 Mesa 24.2.8-1~bpo12+1
00:00:00.096 [I]               egl.c:887  | egl_renderStartup              | EGL APIs: OpenGL OpenGL_ES 
00:00:00.096 [I]               egl.c:958  | egl_renderStartup              | Debug messages disabled, enable with egl:debug=true
00:00:00.126 [I]           eglutil.c:35   | swapWithDamageInit             | Using EGL_KHR_swap_buffers_with_damage
00:00:00.128 [I]              main.c:1590 | lg_run                         | Guest Information:
00:00:00.128 [I]              main.c:1591 | lg_run                         | Version  : B7-rc1
00:00:00.128 [I]              main.c:1612 | lg_run                         | UUID     : c27c4b08-9a3e-4743-8823-d47eac2848c6
00:00:00.128 [I]              main.c:1621 | lg_run                         | CPU Model: AMD Ryzen 7 5700X 8-Core Processor
00:00:00.128 [I]              main.c:1622 | lg_run                         | CPU      : 1 sockets, 4 cores, 8 threads
00:00:00.128 [I]              main.c:1624 | lg_run                         | Using    : DXGI Direct3D 11
00:00:00.128 [I]              main.c:1710 | lg_run                         | OS       : Windows
00:00:00.128 [I]              main.c:1712 | lg_run                         | OS Name  : Windows 10 Pro (Build: 22621) 
00:00:00.128 [I]              main.c:1734 | lg_run                         | Starting session
00:00:00.263 [I]              main.c:710  | main_frameThread               | Format: FRAME_TYPE_BGR_32 1680x1050 (1280x1050) stride:1280 pitch:5120 rotation:0 hdr:0 pq:0