[macos] mouse and keyboard aren't functional after screenshot

[gnawhleinad]

Describe the bug

After screenshot (e.g., ⌘ + shift + 4 of the window with KasmVNC), the VNC session does not register keyboard and mouse events properly. It appears to be a key that is stuck (and I think it is alt).

This may be related to #236.

System Description

$ cat /etc/os-release
NAME="AlmaLinux"
VERSION="9.6 (Sage Margay)"
ID="almalinux"
ID_LIKE="rhel centos fedora"
VERSION_ID="9.6"
PLATFORM_ID="platform:el9"
PRETTY_NAME="AlmaLinux 9.6 (Sage Margay)"
ANSI_COLOR="0;34"
LOGO="fedora-logo-icon"
CPE_NAME="cpe:/o:almalinux:almalinux:9::baseos"
HOME_URL="https://almalinux.org/"
DOCUMENTATION_URL="https://wiki.almalinux.org/"
BUG_REPORT_URL="https://bugs.almalinux.org/"

ALMALINUX_MANTISBT_PROJECT="AlmaLinux-9"
ALMALINUX_MANTISBT_PROJECT_VERSION="9.6"
REDHAT_SUPPORT_PRODUCT="AlmaLinux"
REDHAT_SUPPORT_PRODUCT_VERSION="9.6"
SUPPORT_END=2032-06-01

$ uname -a
Linux i-like-to-move-like-a-robot 5.14.0-570.51.1.el9_6.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Oct 8 09:41:34 EDT 2025 x86_64 x86_64 x86_64 GNU/Linux

KasmVNC Details

$ Xvnc -version

Xvnc KasmVNC 1.3.4.e647af5e281735d1c7fc676ca089201aeae7130a - built Mar 24 2025 13:10:57
Copyright (C) 1999-2018 KasmVNC Team and many others (see README.me)
See http://kasmweb.com for information on KasmVNC.
Underlying X server release 12011000

To Reproduce
Steps to reproduce the behavior (for non-installation issues):

1. Activate session with KasmVNC (i.e., click on the tab with the VNC session)
2. Screenshot e.g., ⌘ + shift + 4 + spacebar + enter
3. Click / type on VNC session

Expected behavior
The mouse and keyboard to work like it did before screenshot.

Browser

• OS: macOS 26.0.1
• Browser: Chrome 141.0.7390.77