Add Last Active Class To Tab

Description

This is a very simple add-on for Tree Style Tab Firefox Extension.

Add a last-active class to the last accessed TST tab:

Install Tree Style Tab – Get this Extension for 🦊 Firefox (en-US)
Go to Tools > Add-Ons > Extensions > Tree Style Tab > Preferences > Extra style rules for sidebar contents

Add:

.tab.last-active {
    background-color: #997719 !important;
}