Tab stacks

Two levels of tabs: a stack is one chip in the tab strip, and its tabs appear in a second bar underneath.

How a stack behaves

A stack shows in the tab strip as a single chip carrying a layers glyph and the number of tabs inside it. Selecting the chip makes the stack active and its tabs appear in a second bar directly under the strip.

This keeps the top row short no matter how many tabs a stack holds — the strip shows your stacks, the second bar shows the tabs of whichever one you are in.

Stacks and plain groups

Every native tab group is presented as a stack by default. Right-click a group's label and choose Change to Tab Group to get Firefox's ordinary inline presentation back, or Change to Tab Stack to return.

The choice is remembered per group and survives restarts.