Mobile Select button exits selection mode immediately on tap

[n8bar]

Summary

Tapping the Select button in the mobile control tray flashes the selection panel open and immediately closes it. Selection mode is unreachable on touch devices.

Repro

• Open TermiWeb on a touch device (observed on Android Brave).
• Tap the Select button in the mobile control tray.
• Selection panel briefly appears, then snaps back to the live terminal view. Selection mode never stays on.

Suspected cause

The Select button's activation handler is registered via bindControlButtonActivation (src/client/main.ts:657) on pointerup. The handler calls setSelectionMode(!selectionMode), which calls renderModifierControls() (src/client/main.ts:1454). renderModifierControls wipes the entire mobile control tray with mobileControls.innerHTML = "" (src/client/main.ts:1519) and re-creates every button, including a freshly bound Select button positioned under the user's finger.

Likely failure mode: the tail of the same gesture (synthesized click, or a follow-up event resolving against the replacement node) lands on the new Select button and triggers setSelectionMode(!selectionMode) a second time, toggling selection mode back off before the user can interact with it.

Supporting observations:

• bindControlButtonActivation has no re-entrancy or "gesture consumed" guard — no pointerId capture, no debounce, no data-handled flag.
• setSelectionMode(true) also calls selectionText.focus() (src/client/main.ts:1448), which on mobile triggers the virtual keyboard and a viewport resize — a secondary candidate path worth ruling out, though no obvious code toggles selection mode off in response.

Suggested fix direction

• Make renderModifierControls not destroy and recreate the active Select button on every state change; toggle classes/labels on the existing nodes instead. This also avoids similar latent issues for other mode-toggle buttons.
• Or, as a narrower fix, guard bindControlButtonActivation against being re-entered by a follow-up event of the same gesture (track pointerId, or set a one-frame "just activated" flag).

Notes

• Found during 0.1.1 dogfooding.
• No native selection workaround on mobile — long-press selection on the xterm.js canvas is not exposed, which is why the Select panel exists in the first place.

[n8bar]

Flagging as a release blocker for the next release per user direction during 2026-05-23 dogfooding triage.