Side-panel focus state diverges between the tool and TUI when hidden with Alt+M

Summary

When the user hides the side panel with Alt+M, an agent can create or focus a different page through the side_panel tool with focus = true. The tool reports the new page as focused, but the TUI deliberately suppresses that focus while hidden. When the user presses Alt+M again, the TUI restores the previously visible page instead of the newly requested page.

Respecting the user's hidden-panel choice is desirable. The bug is that the server-side snapshot and tool output claim one page is focused while the TUI has retained a different page as the one it will display. The agent therefore reports that content was opened or focused even though the user cannot see it.

Environment

• Jcode v0.77.1 (3d164135a)
• Windows x86_64
• Jcode TUI
• Side panel containing more than one page

Steps to reproduce

1. Open side-panel page A.
2. Press Alt+M to hide the side panel.
3. While it is hidden, have the agent create and focus page B:

side_panel action="write" page_id="page-b" title="Page B" focus=true

4. Observe that the tool reports page B as focused:

Side panel: 2 pages
Focused: page-b
* page-b (markdown)
  page-a (markdown)

5. The TUI correctly remains hidden because the user explicitly hid it.
6. Press Alt+M to reopen the side panel.
7. Observe that page A is displayed instead of page B.
8. A subsequent side_panel action="status" can still report page B as focused, despite the TUI showing page A.

Actual behavior

• focus = true updates the persisted/server-side focused_page_id.
• The tool output says the requested page is focused.
• The hidden TUI clears the incoming focused page locally.
• The TUI retains the old last_side_panel_focus_id.
• Reopening with Alt+M restores the old page.
• Tool status and the user-visible TUI disagree about which page is focused.

Expected behavior

The user's Alt+M choice should continue to prevent agents from unexpectedly reopening the panel. However, focus and status should remain internally consistent.

One reasonable behavior would be:

• keep the panel hidden
• record page B as the page to display on the next manual reopen
• report that the panel is hidden and page B is pending or selected
• display page B when the user next presses Alt+M

Alternatively, if focus requests are intentionally ignored while hidden, the tool should report that fact rather than claiming the page is focused.

At minimum, side_panel status should distinguish persisted requested focus from actual client-visible focus.

Technical notes

The side_panel tool defaults focus to true, persists the resulting snapshot, publishes it, and returns status_output(&snapshot). The status is therefore based entirely on the server-side snapshot.

In crates/jcode-tui/src/tui/app/state_ui.rs, set_side_panel_snapshot deliberately clears incoming focus while the panel is user-hidden:

if self.side_panel_user_hidden && snapshot.focused_page_id.is_some() {
    snapshot.focused_page_id = None;
}

Because the snapshot still contains pages, apply_side_panel_snapshot does not clear or replace last_side_panel_focus_id when focus becomes None.

In crates/jcode-tui/src/tui/app/navigation.rs, toggle_side_panel later restores last_side_panel_focus_id, which is still page A.

There is an existing test confirming that a side panel hidden with Alt+M stays hidden across snapshot updates. That desired visibility behavior can remain unchanged. The missing case is a hidden update that explicitly focuses a different page and the resulting server/TUI focus divergence.

Impact

Agents can truthfully receive a successful tool response and then incorrectly tell users that a page was opened or focused. Users reopen the panel and see stale content, making new drafts or files appear missing. The mismatch is especially confusing because side_panel status can confirm a focus state that does not match the rendered TUI.

Start in crates/jcode-tui/src/tui/app/state_ui.rs, especially set_side_panel_snapshot and apply_side_panel_snapshot, then inspect toggle_side_panel in crates/jcode-tui/src/tui/app/navigation.rs. Run the existing test covering Alt+M hidden-panel behavior and add coverage for a hidden snapshot that focuses another page. Done means reopening displays the requested page and tool status no longer conflicts with the TUI's visible focus.