Grey line in prototype preview mode

Hey Chaewon, sorry for the trouble!
Hm, it looks like a similar issue like this thread:

Can you please share a copy of your file and share it with support-share@figma.com as an Editor here so we can try to replicate?
For the context, this can happens because GPUs have known bugs and may cause rendering glitches when using Figma. Please check Figma browser requirements: here

If you are still running into issues, feel also free to reach out the support team so the technical quality can investigate: here

Thank you for your response. However, my issue seems a bit different from the one attached. The attached report discusses lines appearing around the component’s border, but my concern is with a line appearing around the entire Figma window.

This issue occurs on any file and seems to depend on the monitor. The line appears on a monitor with a 3840x1440 resolution and 4K support. It looks like the thickness of the window border changes with different monitor specs, possibly due to resolution differences.

And I don’t think it’s related to the graphics card. Both the monitor with the issue and the one without it are connected to the same desktop.

Could you please check this issue further?

Thanks for the details! Hmm, not sure on my end the root cause of this, it looks like an issue depending on your monitors 🤔 Please also make sure to update your computer and updating your graphics card drivers to see if that helps.

Sure, I suggest you to reach out directly to the support team if the issue still persists by filling this form: here
Our technical quality team can investigate it further. Please make sure to use your Figma email account, mention your desktop specs and monitors affected, if it happens on browser, desktop app or both, so they can take a look. Thank you!