0013. Alt and a number shows that tab

Date: 2026-10-15

Status

Proposed. The user asked for Teleprinter's Alt+1 to Alt+9 (its ADR-0012) to become the standard for Patina apps with tabs, but not for the desktop's bar.

Context

tabs::keys (ADR-0009) gives apps with tabs Ctrl+Shift+T and Ctrl+PageUp/PageDown. Teleprinter added Alt+1 to Alt+9 for jumping straight to a tab, as GNOME Terminal and browsers do. Left there, Notebook and later apps would each add their own, or not, and drift (ADR-0007).

Two things made it more than a key check. egui sends Alt+digit as a key event and then as the digit typed as text, so taking only the key still types the digit. And readline uses Alt+digit for a numeric argument, so a terminal shouldn't lose keys that switch to nothing.

Decision

• tabs::keys takes Alt+1 to Alt+9 and returns TabAction::Show(n) for the nth tab. No change to its signature: apps calling it get the keys with the next Patina release.
• Only when that tab exists. The key and the digit text after it are both consumed; past the last tab both go on to the app's widgets. With one tab, only Alt+1 is taken.
• Alt+9 is the ninth tab, not the last one as in browsers: the user asked for "Alt+1 is first, Alt+2 is second".
• The desktop's bar stays out. It uses TabStrip but not keys (ADR-0012): its tabs are windows, and the compositor owns the desktop's keys. Nothing in Patina changes for it.

Consequences

• Every Patina app that calls keys switches tabs the same way. Notebook gains the keys.
• Alt+1 to Alt+9 no longer reach an app's widgets while those tabs exist. An app needing them can skip keys, as it already could for the others.
• Teleprinter drops its own copy once it depends on this release.