zellij-org/zellij · error · anyhow::Error

Failed to find pane {active_pane_id:?}

Error message

Failed to find pane {active_pane_id:?}

What it means

Returned in execute_focus_pane_and_click_through when get_active_pane_id succeeds but the immediately following tab.get_pane_with_id(active_pane_id) fails. The focus bookkeeping reports an active pane that no longer exists in the pane maps - a genuine internal desync between the active-pane pointer and pane storage, more suspicious than a simple missing focus.

Source

Thrown at zellij-server/src/tab/mouse_handler.rs:977

        Self::focus_pane_at(tab, &position, client_id).with_context(err_context)?;

        let osc133_command_selection = tab.osc133_command_selection;
        let word_separators = tab.word_separators.clone();
        if let Some(pane_at_position) = Self::unselectable_pane_at_position(tab, &position) {
            let relative_position = pane_at_position.relative_position(&position);
            pane_at_position.set_selection_options(osc133_command_selection, &word_separators);
            pane_at_position.start_selection(&relative_position, client_id);
            return Ok(MouseEffect::state_changed());
        }

        let active_pane_id = tab
            .get_active_pane_id(client_id)
            .ok_or_else(|| anyhow!("Failed to find active pane"))
            .with_context(err_context)?;

        let pane = tab
            .get_pane_with_id(active_pane_id)
            .ok_or_else(|| anyhow!("Failed to find pane {active_pane_id:?}"))
            .with_context(err_context)?;

        let terminal_wants_mouse = pane.terminal_emulator_wants_mouse();

        if terminal_wants_mouse {
            let relative_position = pane.relative_position(&click_event.position);
            let mut event_for_pane = click_event;
            event_for_pane.position = relative_position;
            if let Some(mouse_event) = pane.mouse_event(&event_for_pane, client_id) {
                if !pane.position_is_on_frame(&click_event.position) {
                    tab.write_to_active_terminal(&None, mouse_event.into_bytes(), false, client_id)
                        .with_context(err_context)?;
                }
            }
        } else {
            if let Some(pane) = tab.get_pane_with_id_mut(active_pane_id) {
                let relative_position = pane.relative_position(&position);
                pane.set_selection_options(osc133_command_selection, &word_separators);

View on GitHub (pinned to 98a0837077)

Solutions

  1. Reproduce deliberately: open one pane, close it, and click rapidly - if the error appears, focus reassignment on close is the culprit path
  2. Upgrade zellij first; active-pointer hygiene around pane close has seen multiple fixes
  3. If embedding, always close panes through Tab's close APIs (which fix focus), never by mutating pane grids directly
  4. Report upstream with reproduction if it persists on the latest version, since this indicates a real desync bug

Example fix

// before
let pane = tab
    .get_pane_with_id(active_pane_id)
    .ok_or_else(|| anyhow!("Failed to find pane {active_pane_id:?}"))
    .with_context(err_context)?;

// after: self-heal by falling back to the first selectable pane
let pane = match tab.get_pane_with_id(active_pane_id) {
    Some(p) => p,
    None => match tab.get_active_pane_id_or_first_selectable(client_id) {
        Some(id) => tab.get_pane_with_id(id).ok_or_else(|| anyhow!("no pane available"))?,
        None => return Ok(MouseEffect::default()),
    },
};
Defensive patterns

Strategy: try-catch

Validate before calling

// validate both pointers resolve before routing the click
let pane_id = match tab.get_active_pane_id_or_first_selectable(client_id) {
    Some(id) if tab.get_pane_with_id(id).is_some() => id,
    _ => return Ok(MouseEffect::default()),
};

Type guard

fn active_pointer_is_consistent(tab: &Tab, client_id: ClientId) -> bool {
    match tab.get_active_pane_id(client_id) {
        Some(id) => tab.get_pane_with_id(id).is_some(),
        None => false,
    }
}

Try / catch

// heal-and-continue pattern for pointer/storage desync
let pane = tab
    .get_pane_with_id(active_pane_id)
    .or_else(|| {
        tab.get_active_pane_id_or_first_selectable(client_id)
            .and_then(|id| tab.get_pane_with_id(id))
    })
    .ok_or_else(|| anyhow!("no pane available"))?;

Prevention

When it happens

Trigger: Any click-through path executed in the window between a pane being removed from the pane grids and the client's active-pane pointer being reassigned. The two lookups happen back-to-back, so the pane must exit in between or the pointer is stale from an earlier race.

Common situations: Pane exit racing a click; plugins or layouts removing panes without going through the normal focus-reassignment path; session resurrection restoring an active-pane pointer to a pane that was not resurrected; desync induced by rapid close/reopen cycles.

Related errors

AI-assisted analysis of zellij-org/zellij@98a0837077 (2026-08-16). Data as JSON: /api/errors/31007ae6e057f9e6. Report an issue: GitHub.