This is a fun one: I usually run Zorin OS 18.1 using Wayland, but today I had to switch to an X11 session due to an incompatible app (Rambox 2.6.3). Everything was working fine, until the moment I brought my notebook back to my desk and connected my secondary display.
The SECONDARY screen jitters/jumps/shakes whenever the mouse cursor hovers over the dock on the PRIMARY screen. Quite funny, but annoying. I managed to capture it on video; get it here:
" Screen jitter on a secondary display in Gnome 46 on X11 is typically caused by driver conflicts , incorrect scaling settings , or hybrid graphics management issues.
Primary Causes and Solutions
Monitor Configuration and Refresh Rates : Ensure the external monitor is set to its manufacturer-recommended refresh rate and resolution. Incorrect or manually altered modelines can cause flickering and jitter. Press the monitor's physical Auto button to reset its internal settings to default, which often resolves basic synchronization issues.
Graphics Driver Conflicts : If using Intel integrated graphics , ensure the xf86-video-intel package is uninstalled , as it often interferes with the default modesetting driver and causes UI lag or flickering. For systems with NVIDIA GPUs, switching to NVIDIA-only mode using optimus-manager (instead of hybrid mode) often eliminates lag and stuttering on external displays.
Scaling and HiDPI Settings : HiDPI or fractional scaling settings can cause instability on X11 with certain hardware. Try disabling HiDPI scaling on the laptop's internal screen or ensuring both monitors are set to the same resolution to rule out scaling-related jitter. Installing mutter-x11-scaling has been noted to resolve smoothness issues on high-resolution displays in some Arch-based environments.
NVIDIA RandR Bug : If using an NVIDIA GPU, stuttering and jitter when launching specific applications (like Rambox) while a second monitor is connected may be due to a known NVIDIA RandR implementation bug . Disabling RandR in the application's configuration (e.g., via Wine registry settings for Proton/Wine apps) or physically disconnecting the secondary monitor can isolate this cause.
Recommended Troubleshooting Steps
Check GPU Mode : If you have a hybrid laptop (Intel + NVIDIA), use optimus-manager to switch to NVIDIA mode and reboot.
Verify Drivers : Run lspci to identify your GPU. Remove xf86-video-ati or xf86-video-intel if present, as they interfere with modesetting .
Adjust Display Settings : In Gnome Settings , ensure the external monitor is using its native resolution and refresh rate. Try disabling Fractional Scaling if enabled.
Test Cable and Port : Try a different HDMI/DisplayPort cable or port, as faulty connections can cause signal instability that manifests as jitter.
