microsoft / microsoft/agent-framework
DevUI theme keeps defaulting to Dark instead of respecting System mode
@victordibia is already working on this.
Since Feb 20, 2026.
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Description
## Bug report
DevUI keeps defaulting to Dark mode after restarting, even when I previously selected **System** mode.
## Repro steps
1. Open DevUI.
2. Change theme to **System** mode.
3. Use DevUI normally (theme selection is respected in this session).
4. Restart/reopen DevUI.
5. Observe theme selection on load.
## Actual behavior
- ✅ DevUI respects the selected theme mode within the current session.
- ❌ After restart, DevUI defaults back to **Dark** mode.
## Expected behavior
DevUI should persist and restore the previously selected theme mode (including **System**) across restarts.
## Suggestion
Persist the user theme preference in localStorage (or a cookie) and restore it on startup.
Thanks!
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