Can't see all my browser windows when sharing screen

[Cathal16]

When I click on the share screen button, I can't see all my open windows to select the one I want to share. There is an icon for microsoft edge and one for chrome and when I hover over the icons a dialogue box gives the number of open pages for that browser but I can't see or select any of the pages. How can I see the individual windows and select the one I want to share?