Webex Application Version: 44.1.0.28423, Windows 10
This issue affects the light themes, and I think effects the dark themes in Windows dark mode too. The Webex application does not have a border when in a window like all my other applications. This causes the bottom of the current light themes to blend into other light colored windows in the background. This never used to be an issue, but has not be been fixed for a number of releases now. See the attachments with the bottom right corner of the Webex app on top of this browser window, and the Acrobat Reader window that has a blue border.