I have a tab control in my custom theme, which is based on a standard theme. The original had square tabs and I want to make them rounded.
My problem is that there's some kind of background box on the tab control and I can't find the setting to turn it off or eliminate line and fill for the box.
Here's the way it turns out:
You can see the box to the right of the last tab, and also the line along the top of the box between the rounded edges.
Here's an example of that box being invisible:
Where is the setting to change this?