URL bar flickers when cursor is at specific position

[Lordlorio]

Captchas

• [x] I have read the instructions.
• [x] I have searched existing issues and avoided creating duplicates.
• [x] I am not filing an enhancement request.
• [ ] I have checked that this issue cannot be reproduced on Mozilla Firefox.
• [x] I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

When the cursor is positioned at a specific point inside the URL bar, the content begins to flicker and is repeatedly displayed It looks like the URL keeps respawning or flashing in a loop. To reproduce the bug, you must be in compact mode. Then hide the both.

https://github.com/user-attachments/assets/cd66896e-8668-4d2c-ad88-efdb43ac018e

Version

1.13t (Firefox 138.0.4) (2025-05-22) (64-bit)

What platform are you seeing the problem on?

Windows - x64

What component is this issue related to?

URL Bar

Relevant log output if applicable