[BUG] Ctrl+click on sidebar session no longer opens split pane on Windows (v1.7196.0)

Environment

• Claude Code Desktop version: 1.7196.0 (2dbd78)
• OS: Windows 11
• Git for Windows: 2.53.0.windows.2

Expected behavior

Per the official documentation at https://code.claude.com/docs/en/desktop:

To view two sessions at once, hold Cmd on macOS or Ctrl on Windows and click a session in the sidebar. The session opens in a second pane alongside the one you already have open.

Actual behavior

Holding Ctrl and clicking a session in the sidebar highlights/selects the session but does NOT open a second pane. Only the originally focused session remains visible in the main area. Multiple selected sessions appear with a "selected" visual state but no split view is created.

Regression note

User reports this feature worked correctly a few days ago on an earlier build. Appears to be a recent regression.

Steps to reproduce

1. Open Claude Code Desktop on Windows
2. Open any session from the sidebar so it shows in the main area
3. Hold Ctrl, click another session in the sidebar
4. Observe: the additional session appears selected but is NOT opened as a split pane

Verification of UI alternatives

• Keyboard shortcuts (Ctrl+/) panel: lists Focus next split pane (Ctrl+]), Focus previous split pane (Ctrl+[), and Close pane (Ctrl+\), but NO shortcut for OPENING a split pane from a sidebar session
• Right-click context menu on sidebar session: shows Open in (VS Code/Explorer), Move up, Unpin, Mark as unread, Rename, Fork, Move to group, Archive, Delete. No "Open in split" / "Open beside" / equivalent
• Views menu in session toolbar: opens diff/preview/terminal/file/side-chat panes within the same session, but no option to open another session as a split pane

So the only documented way to open a session as a split pane (Ctrl+click in sidebar) is non-functional, and there is no alternative UI affordance exposed in this build.

Potentially related issues

• #30154 (FEATURE: Multi-window support in Claude Code Desktop)
• #50388 (+ New Session button unresponsive on Windows 11)
• #53717 (Sessions in sidebar but content missing on Windows after auto-update)

These suggest a pattern of sidebar/session-management regressions in recent Windows builds.