Firefox as of 2025 has issues with Nvidia graphics drivers. This results in issues with WebGL. AvPlan's web interface uses WebGL so you may see this :
Note that this is NOT an AvPlan EFB bug, it is a driver issue with Firefox and Nvidia. Any application using WebGL will experience the problem.
The fix, as of April 2026, is to alter the settings in Firefox using about:config
Set gfx.webrender.all to "true"
Restart Firefox and that should fix it. It did with our testing and Firefox 149.0 with the Nvidia Studio driver version anyway, using Nvidea Studio 595.79 driver for an RTX graphics card.
Many gaming and high performance laptop PCs have Nvidia graphics cards and drivers, as do many desktops.
The same issue may appear on Linux systems also with Nvidia graphics cards and drivers. See https://mvysny.github.io/firefox-hw-acceleration/ for more information.