Hello, although I also want to add context menus to the tabs, I will only do it if it is possible to set checked/unchecked/selected states there too. This is not the case with current Firefox versions, but it will be in the future, and I will be one of the firsts to support it.

As for the tab colors, I cannot modify it (WebExtension limitation), but I already set a small icon in the beginning of the tab title to mark tabs that are set to reload.