ComboBox - strange artifacts (3.1.0 release)

[bebenins]

You can see it without changing MaterialDesignPaper but I changed it to red to highlight the issue.

1. Vertical line.
2. Don't even know how to call these. They are in all 4 corners... some sort of "notches" of 1 pixel perhaps.

Just FYI, I see it with Font 13 and 16, same on both.

[soi013]

Did you use dialog?

#1199 (comment)

[bebenins]

Did you use dialog?

#1199 (comment)

Not sure what you mean. I'm using a standard ComboBox.
UseLayoutRounding="True" has been set in my apps since the very beginning. This issue only showed up after upgrading to 3.1.0.

[soi013]

Probably, vertical line is deleted in newest repository.
And other notches is fixed by my PR.