Resizing the windows larger results in blank background

[lukeu]

Steps

1. Resize the window larger

Description
I just see a thin border and the background shows through where the new area should be painted. The original area continues to repaint and clips. After restarting calc, it repaints correctly at the new size, but resizing it larger again fails. A reboot of Windows may help for some time until it starts happening again.

Screenshots

Device and Application Information:

• OS Build: 10.0.17134.0
• Architecture: X64
• Application Version: 10.1812.10048.0
• Graphics card: GTX 660 nVidia driver version: 399.24 (2x 2K monitors, DPI scaling 115%)

I've also observed the issue an a Dell XPS 15 laptop, running on only its Intel embedded graphics. (DPI scaling 250%) so it doesn't seem device specific. Has been happening for over a year, across I think 3x (?) major Windows 10 updates.

[MicrosoftIssueBot]

This is your friendly Microsoft Issue Bot. I've seen this issue come in and have gone to tell a human about it.

[grochocki]

Thanks for the report and thorough device details! We believe this bug in a piece of code outside of the Calculator codebase. Resolving as external, but routing to appropriate internal team to investigate further.