When executing the example projects included in the repo on PowerShell or cmd in the Windows Terminal (this, here is the code) some anomalies happen:

OS: Windows 10 1909
Terminal.Gui version: 0.24.0 (dev)
I already checked and it's a very odd behavior indeed
Same behavior when running the sample inside WSL inside Windows Terminal:

However, the thumb in the vertical scroll bar is correctly rendered (whereas it is not in a standard command prompt):

Well, that may be a problem with Consolas (missing support for fallback characters?); once I change my command prompt font from Consolas to Fira Code, everything is fine:

Mouse support isn't supported in Windows Terminal but it's being worked on - confirmed:
https://twitter.com/cinnamon_msft/status/1237253970759782401?s=19
Confirmed mouse is still not working in Windows Terminal 1.0 or Windows Terminal (Preview) Version: 1.0.1402.0.
This really is a setback.
This is the Windows Terminal bug, for clarity: https://github.com/microsoft/terminal/issues/376
Until this is fixed in Windows Terminal, there's nothing we can do about it.
For now I vote we do NOT make this a ship-blocker for 1.0.
I'm removing the 1.0 label. If you disagree please reply with why.
Most helpful comment
Until this is fixed in Windows Terminal, there's nothing we can do about it.
For now I vote we do NOT make this a ship-blocker for 1.0.
I'm removing the 1.0 label. If you disagree please reply with why.