Rendering problem of WinForms checkbox in DPI aware Win10 application

This is a crosspost from https://connect.microsoft.com/VisualStudio/feedback/details/3100708/rendering-problem-of-winforms-checkbox-in-dpi-aware-application, as MS support told me to ask the question in the forums for workarounds. I am not sure whether I am at the correct place here, because I don't find a matching category.


I try to add Win 10 DPI awareness to our application, following the code sample found here: https://emoacht.wordpress.com/2013/10/30/per-monitor-dpi-aware-in-windows-forms/


If you start the sample program from this website on a screen with 100% scale and move it to a screen with 200% scale, the checkbox glyphs still have their size of 13 pixel. See attached screenshot.

My only modification to the sample: I added this to the "app.config" file:

<appSettings>
<add key="EnableWindowsFormsHighDpiAutoResizing" value="true" />
</appSettings>


The cause seems to be hidden in "CheckboxRenderer.GetGlyphSize", which calls "VisualStyleRenderer.GetPartSize". Either this method has a problem or the call to the native method "GetThemePartSize" causes the problem. The DPI of the current display is not checked.


Response from MS support: We are able to reproduce this issue and are looking into HDPI improvements in a future release.


But does anybody have a workaround for this?


Best regards


Wolfgang

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