Maximize on HiDPI monitor doesn't work as expected

[vchirikov]

Hi I have three monitors, 2 of them 2560x1440 with 100% scale and third has 200% scale and 3840x2160 resolution and on third monitor I had a issue. Maximize window only works on a half of the monitor:

issue.webm

[vchirikov]

Looks like you use one DPI for all monitors

https://github.com/cairoshell/ManagedShell/blob/aec89f11a7cb227addf6669df6ee1884491aa76d/src/ManagedShell.Common/Helpers/DpiHelper.cs#L72-L78

which isn't true, each monitor might have different dpi scale

[vchirikov]

Oh, I see you try to get WM_DPICHANGED later, but looks like it's doesn't work well.
https://source.dot.net/#PresentationFramework/System/Windows/Window.cs,c9ce03bb401c4790,references
Maybe this could help to do it right without WM_DPICHANGED hack?
cc: @dremin

[ejrv]

bro replies to himself 💀

[dremin]

@vchirikov I've seen this bug as well, I suspect either we are telling Windows incorrect appbar metrics, or there is a new bug in Explorer's appbar implementation with mixed DPI.