Background color attribute is filled incorrectly when resizing window

Windows Terminal version

1.20.11781.0

Windows build number

10.0.19045.4651

Other Software

print("\033[?1049h")
print("\033[31m")
print("test")

Steps to reproduce

Use Virtual Terminal Sequences. Change background, print some text, resize window (rows+1) or maximize window.

Expected Behavior

The following result was obtained using the Windows API:

set_console_text_attribute(hConsoleOutput, WHITE_FORE + RED_BACK + NORMAL_STYLE)

Actual Behavior

1 row red, the following ones are already filled in correctly.

maximize window.

restoring the window and then maximizing it again fixes this error.

but it doesn't help for a single row.

It is worth summing up. Attributes are filled into new buffer cells correctly when using Windows Console Api. When using virtual codes, the described problem is observed. Also in Windows Console (cmd.exe) any window scaling, in both Windows Api and virtual codes, causes attributes to be filled incorrectly.

But this is known, and I understand that you are releasing all fixes in Windows Terminal.

Start by reproducing the issue with the supplied Python Virtual Terminal Sequences, changing the background and resizing or maximizing the Windows Terminal window. Compare behavior with the Windows Console API and cmd.exe cases described in the report. Done means newly created or resized buffer cells retain the expected background attribute for both single-row and larger resizes.