Or something like that. I have to confess that I hadn't realized that now only the active tab has rounded corners. the bottom inverse rounded corners on the active tab are nice, but that might be way too complicated.
The effect in Joplin would be stronger if there wasn't the menu bar above anything, but it sounds like nothing can be done about that.
Any way, thanks so much for the plugin. Feel free to ignore this request if you don't think it would be beneficial to most users.