This glitch happens on macOS Golden Gate 27.0.1, it wasn't an option in the version selection
When choosing a tab layout (Standard, Compact, Vertical), the purple box that appears when you hover over the options sometimes flickers. I couldn't reliably get the bug to happen, though.
The selection box only flickers some of the time, but my tests were giving inconsistent results on whether it would flicker or not.
Version 1.1.3.152
