ToolTip closes immediately in high DPI

[SamBent]

Fixes #6220

Description

In high DPI environment, most tooltips opened by the mouse close immediately.

This is because the SafeArea uses unscaled coordinates, while the current mouse point uses scaled coordinates. In high DPI, these are different, leading to false negatives from the containment test "is the mouse within the SafeArea".

Fixed by using unscaled coordinates for the mouse point. (And incidentally improving the perf by avoiding a lot of unnecessary transformations into, and out of, scaled coordinates.)

Customer Impact

Make ToolTips great again (in high DPI).

Regression

Regression in PR #5931.

Testing

Tested by hand, but thoroughly, in .NET 4.8.1. The automated tests don't cover high DPI, unless you explicitly run them on a machine whose primary monitor is high DPI.

This is a straightforward port of the .NET Fx fix, but should be tested in .NET Core anyway.

Risk

[barnum1]

Is there an estimated date for a version of .NET with a fix for this?
It's very awkward to explain to our users why tooltips do not work in our application.
Thanks.

[singhashish-wpf]

We are trying to push this to 6.0.5; may servicing release. Will keep you posted.

[lindexi]

I picked this PR to my application and I tested the my app for a week. This issue has been fixed and no new issues have been introduced.

[AlquistArj]

I'm also seeing the disappearing Tooltips in my WPF apps (using various versions of .NET from 4 up to 4.8). These have worked for years but stopped recently for some reason. Tooltips continue to work in Winforms and in WPF apps built with .NET5/6.

[barnum1]

We are trying to push this to 6.0.5; may servicing release. Will keep you posted.

Hi, when is the estimated date for 6.0.5 release?

[barnum1]

@singhashish-wpf
Could you please give us an estimated date of 6.0.5 release?
It is very difficult for us to explain this malfunction of our application to our users.
(We have no way to pull a PR and build a version ourselves.)

[singhashish-wpf]

You can expect it to be out by tomorrow PST.

@singhashish-wpf Ashish Singh FTE Could you please give us an estimated date of 6.0.5 release? It is very difficult for us to explain this malfunction of our application to our users. (We have no way to pull a PR and build a version ourselves.)