[BUG] Screen scaling problem

[Descolada]

[BUG] Screen scaling problem

[DaveTryon]

Hi, @Descolada! We've looked into this and there appears to be a problem in the interaction between Chromium and Windows. Here's another way to see the same sort of problem without using Accessibility Insights:

• Start Magnifier on one one display and resize it to fill the top half of the display
• Go to its settings (click the gear button)
• Set the view to "Docked"
• Uncheck "Mouse pointer"
• Run a Chromium app (like opening this web page in Chrome) on the other display
• Use the tab key to navigate around the Chromium app, and watch how Magnifier responds.

When things are working correctly, the cursor will remain centered in the Magnifier window. When I do this in an app using WPF or Windows forms, it works very well. When I do this in Chrome, the results are mixed. Some elements (like edit controls or images) usually do a good job of staying centered. Other elements (like links or buttons) often don't fare as well. The effect can be exaggerated by resizing the browser window to occupy just the center 50% of the screen horizontally and vertically. Magnifier will often show parts of the screen that aren't even inside the Chrome window.

Trying to get this fixed may be difficult. Chromium supports an accessibility technology called IAccessible2, which is not directly supported by Windows. Recent versions of Windows provide a mapping layer that converts IAccessible2 to UIA, and an error in either layer could cause the element's BoundingRectangle property to report incorrectly scaled coordinates. I hope this helps explain what's going on--Accessibility Insights is just using the bad data that it's receiving from UIA.

Thanks for helping us improve Accessibility Insights!

[sms2000]

Same issue happens with Outlook 365 Beta.
As soon as the Outlook is of Microsoft wee may expect the fully correct behavior for MSAA on multiple displays with various DPIs.

The original Outlook 365 works OK.