Tab groups

Related tabs stay together as a group, drawn as a colored band along the top of every member tab. The band is the same color and full strength on every member, active or not, so a group reads as one connected run in the strip.

You don't manage groups directly — they follow from how tabs are created:

• The root group. The startup janus tab founds the first group, colored after its own dot.
• New tabs join their creator's group. A tab made with agent (or by opening a file or page) joins the group of the tab you ran the command from. Creation is transitive: a chain of agents spawned from one another all share one group.
• Profiles get their own group. profile launch places all of a profile's tabs into one new group, so a launched profile reads as its own band in the strip — see Profiles.

A group's band color is fixed when the group is created (the color of its first member) and never shifts afterward, even as tabs are reordered or closed.

Groups also stay contiguous. A new tab is inserted directly after the last tab of its group, and reordering with Ctrl+← / Ctrl+→ only swaps a tab with a neighbor in the same group — you can rearrange within a band, but never drag a tab out of it.

Groups persist: on janus --relaunch, every restored tab keeps its group and band color, so the strip comes back exactly as you left it.