TabPanel background doesn't match window background color

Hi, This is my first post and I am writing my first app for desktop using Xojo 3.1 on macOS Catalina 10.15.4 running in light mode

When I add a tab panel to a window on the background colors do not match. The Tab panel is a darker grey than the window background

How can I make the colors match. My application looks a bit weird with two different grey tones

Is this by design?

Many Thanks

Stu

That’s how it’s supposed to look on macOS.
https://www.google.com/search?q=mac+tab+panel&tbm=isch

Yes. See the HIG@Apple: https://developer.apple.com/design/human-interface-guidelines/macos/windows-and-views/tab-views/

Thanks Guys - came from Windows go figure.