This issue has been reproduced during testing with Firefox on Parrot OS. The remote browser session remains active, but its display may not render correctly when the local Firefox window is operating at higher resolutions.
Symptoms
- The Remote Browser session connects successfully, but the remote browser area appears black or incorrectly rendered.
- The remote browser application is running even though it is not visible.
- Reducing the size of the local Firefox window can cause the remote browser to appear.
- After resizing the local Firefox window, the remote application may scale to the available session area and become usable.
- The problem is dependent on the local browser and display resolution rather than the remote browser instance itself.
Affected clients
The issue has been reproduced using Firefox on Debian-based Linux at higher local display resolutions.
Testing produced the following results:
Client Operating Local Monitor Resolution Result system browser
HP Omen Debian-based Linux Firefox Samsung 2560x1440 Black U28E570D remote display
HP Omen Debian-based Linux Firefox Samsung 1920x1080 Working U28E570D
HP Omen Debian-based Linux Chromium Samsung 2560x1440 Working U28E570D
HP Debian-based Linux Firefox Dell 1920x1080 Working EliteBook S2719DC
HP Debian-based Linux Firefox Dell 2048x1089 Working EliteBook S2719DC
HP Omen Windows 11 Firefox Samsung 3840x2160 Working U28E570D
HP Omen Windows 11 Chrome Samsung 3840x2160 Working U28E570D
The Dell S2719DC test system did not offer 2560x1440 as an available resolution, so Firefox could not be tested with that monitor at 2560x1440.
Known working configurations
The following configurations have been confirmed to work during testing:
- Chromium on Debian-based Linux at 2560x1440.
- Firefox on Debian-based Linux at 1920x1080.
- Firefox on Debian-based Linux at 2048x1089 in the tested Dell monitor configuration.
- Firefox on Windows 11 at 3840x2160.
- Chrome on Windows 11 at 3840x2160.
Using Chromium on Debian-based Linux is currently the recommended workaround when the problem occurs.
Cause/status
Known issue --- workaround available.
Testing indicates that the Remote Browser instance and remote application are operating correctly.
The same remote environment works at higher resolutions when Chromium is used on Debian-based Linux. Firefox and Chrome also work at 3840x2160 when the same HP Omen and Samsung U28E570D monitor are used with Windows 11.
Disabling hardware acceleration in Firefox did not resolve the problem.
These results indicate a compatibility or rendering issue specific to Firefox on the tested Linux/Debian-based Linux environment when using a sufficiently large browser viewport.
The precise underlying cause has not yet been established. The issue should therefore not currently be attributed specifically to Firefox WebRender, WebGL, the Linux graphics driver, or the remote streaming technology.
Workaround
If the remote browser displays a black screen when using Firefox on Linux:
- Use a current Chromium-based browser. Chromium has been confirmed to work at 2560x1440 on the same Debian-based Linux system where Firefox displays a black remote session.
- If Firefox must be used, reduce the local display resolution. 1920x1080 has been confirmed to work on the affected Debian-based Linux system.
- Alternatively, reduce the size of the local Firefox window. Resizing the window can cause the remote browser display to become visible and usable.
Changing Firefox's hardware-acceleration setting is not currently considered a workaround, as disabling hardware acceleration did not resolve the issue during testing.
Troubleshooting
- Confirm that the remote session connects successfully and that the problem is limited to the remote display area.
- Reduce the size of the local Firefox window. If the remote browser becomes visible after resizing, the problem may match this known issue.
- Test Firefox at a local display resolution of 1920x1080.
- Test the same remote session using an up-to-date Chromium-based browser without changing the local display resolution.
- If Chromium works at the higher resolution while Firefox does not, use Chromium as the current workaround.
- When contacting support, record the local operating system, browser name and version, monitor model, local display resolution, display scaling, and whether reducing the Firefox window size causes the remote display to appear.
- If possible, also report whether the Linux desktop session is using X11 or Wayland. This information may assist further investigation.
The issue is considered client-side or client-browser-specific based on the configurations tested so far. No changes to the Remote Browser instance are currently required.