Compatibility Report

• Name of the game with compatibility issues: The Lord of the Rings Online
• Steam AppID of the game: 212500

System Information

• GPU: GTX 970
• Driver/LLVM version: 4.6.0 NVIDIA 440.82
• Kernel version: 5.7.0-3-MANJARO
• Link to full system information report: Gist
• Proton version: 5.0.9

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

Symptoms

Using the Overlay to browse the web on about 3-5+ tabs starts to cause significant FPS drops in-game, even after all the tabs and browser are closed.
The FPS drops are interesting because they only occur when the mouse moves, if I leave the mouse still the FPS stays the same even when moving by keyboard, any movement by the mouse and there's significant drops and choppiness.

Reproduction

1. Launch LOTRO
2. Start using the overlay, open 3+ tabs and go to different sites (e.g. reddit, wikipedia etc)
3. Close tabs and go back to game, move mouse around