Dialog: Focustrap doesnt work with only one tabbable component.

[AndreHogberg]

Describe the bug

When using the dialog component and you only got the close button, you can lose the focus trapping which makes you lose the ability to close the dialog using escape. It works fine with 2 buttons and 0 buttons. I tried looking at the code, and I suspect it is the following line:

bits-ui/packages/bits-ui/src/lib/bits/utilities/focus-scope/focus-scope.svelte.ts

Line 161 in 798d695

if (tabbables.length < 2) return;

Reproduction

https://stackblitz.com/edit/nrnpy3gb?file=src%2Froutes%2F%2Bpage.svelte

Logs

System Info

System:
    OS: Linux 6.6 Ubuntu 24.04.3 LTS 24.04.3 LTS (Noble Numbat)
    CPU: (32) x64 AMD Ryzen 9 9950X3D 16-Core Processor
    Memory: 25.10 GB / 30.17 GB
    Container: Yes
    Shell: 5.2.21 - /bin/bash
  Binaries:
    Node: 24.11.0 - /home/arkuna/.nvm/versions/node/v24.11.0/bin/node
    npm: 11.6.1 - /home/arkuna/.nvm/versions/node/v24.11.0/bin/npm
    pnpm: 10.20.0 - /home/arkuna/.local/share/pnpm/pnpm
    bun: 1.3.3 - /home/arkuna/.bun/bin/bun
  npmPackages:
    @sveltejs/kit: ^2.48.5 => 2.49.0 
    bits-ui: ^2.14.4 => 2.14.4 
    svelte: ^5.43.8 => 5.43.14

Severity

annoyance

[huntabyte]

Oof yes that line would be the culprit, though we'll need to add logic to just do nothing if that element is already focused and they are trying to move focus! Nice catch!