Closing first tab closes whole window
Vivaldi Version: 5.4.2753.40 (Stable channel) (x86_64)
Operating System: macOS Monterey v12.5.1
Open and maximise a Vivaldi window.
Open several tabs in that window.
Try to close first tab only by clicking on the tab where the website's icon is.
Closes only that tab.
Closes entire window.
Move the mouse to the top of the screen until the Vivaldi menu appears. This also exposes the three coloured 'close / minimise' buttons on the top left and moves the tabs over a bit to the right. Then clicking on the tab's close button works as expected.
Normally, website icon gets replaced by X symbol when hovering the mouse over it. But that doesn't usually happen on the first tab in maximised window. When that does happen, the expected behaviour of closing just that tab happens.
I suspect that it has something to do with the fact that the position of the (hidden) close window button is at the same spot as the 'close tab' button.