My one request: let us pick any color, not just the nine preset swatches.

Why this would help:

• Nine colors run out quickly for anyone with lots of islands, and a few of the presets look similar at a glance.
• GX is all about personalization (themes, mods, accent colors, custom cursors), so being able to match island colors to your own theme fits right in.
• Other browsers already allow full color choice for tab groups, so this would close that gap.

Suggested implementation:

• Keep the nine presets as they are.
• Add a "+" or "Custom" swatch at the end that opens a color picker with a hex input field.
• Remember recently used custom colors so they're quick to reapply.

It would also be great if extensions could set custom colors through the tab groups API, but the built-in picker matters most.

Thanks for considering it!