ChatGPT desktop app window border appears on second monitor when maximized

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26.915.31945

What subscription do you have?

Plus

What platform is your computer?

No response

What issue are you seeing?

Hi. I found a reproducible multi-monitor UI issue in the ChatGPT desktop app on Windows 11.
System:

• Windows 11 25H2
• Acer Predator Triton 300 SE PT314-51s
• NVIDIA GeForce RTX 3060 Laptop GPU
• 14" laptop display + 27" external monitor
• Extended desktop mode
• Laptop display scaling: 150%
• External display scaling: 100%
  Problem:
  When the ChatGPT desktop app is maximized on one monitor, a thin vertical part of the app window border remains visible on the adjacent second monitor.
  The issue persists even if both displays are set to 100% scaling.
  I also tested:
• different monitor alignment in Windows
• disabling window shadows
• different High DPI compatibility settings
• reopening and moving the app between monitors
  None of these fixes the issue.
  Interestingly, the problem disappears when I press F11 and enter true fullscreen mode.
  This suggests that the issue may be related to the maximized window frame/border rendering in a multi-monitor configuration.
  I can provide screenshots if needed.

What steps can reproduce the bug?

Feedback ID: no-active-thread-01a0ba64-9bcf-7923-92a1-7ab3ef084609

What is the expected behavior?

No response

Additional information

No response

Start by reproducing the issue on Windows 11 with an extended laptop and external display, using different scaling settings and a maximized app window. Compare the maximized state with F11 fullscreen and monitor alignment changes. Done means no portion of the app border remains visible on the adjacent monitor while maximized.