2.12.0.1 version. Icons for control buttons in the side bar under "Open Tabs" or "Unstashed Tabs" are not visible. You can only tell what the button does by waiting for a mouse-over tool tip. I wanted to try out the full page tab group management but am uninstalling before finding it. RAM use was not affected by activating this extension.
Afraid I'm not sure what you mean by "the icons are not visible"—I can't offer help in review comments (there's not enough space), but please feel free to open an issue on GitHub and I'd be happy to look into it!
