Bug: resizing doesn't work properly in Windows Terminal

[Shorotshishir]

Environment

Windows build number: [Version 10.0.18362.175]
Windows Terminal version (0.2.1715.0):

Steps to reproduce

open any terminal (PowerShell/cmd/wsl). type any command (e.g. dir, ver, uname) and enter. resize the app window to the minimum and gradually enlarge the window.

Expected behavior

information should stay the same. shouldn't break and should render all the characters like below

Actual behavior

breaks apart and doesn't render properly

[JushBJJ]

Kinda like #1433 but this time, its with all command lines.

[HBelusca]

Here is a screen movie to illustrate the described problems above (note how the scrollbar modifies):

Auxiliary observations:

• VtPipeTerm.exe misbehaves as well when resizing either of the background host window, or the front window.
• OpenConsole.exe does not have this problem, but acts very slowly when trying to resize the window (why?)

[DHowett-MSFT]

OpenConsole in debug or in release?

If vtpipeterm is hitting it too, that's definitely a conpty issue.

[HBelusca]

(I should have added that I was testing with master a5f31f7 .

OpenConsole in debug or in release?

OK the slowness was just in debug mode; I recompiled and re-tested in release mode and it's back to the usual speed ("fast").

If vtpipeterm is hitting it too, that's definitely a conpty issue.

For this my interpretation of what's going on may be erroneous because I'm also looking at the background host window, while the front window only allows resizing but not scrolling. See the animation below.