[Bug]: Sidebar opens and/or focusses MR every time opening a thread

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

When having multiple conversations with multiple MRs, the new MR auto-assign feature (I like it very much!) always force-opens the MR sidebar.

Even if it was closed 10 times before. Even if no sidebar was open before. Even if the MR is already open in a sidebar tab. Sometimes it even opens the same MR in multiple tabs (which is not possible normally via the GUI :D)

Expected behavior

It shall respect my previously opened tab (even if opening it in the background) and not force open a sidebar every time its opened.

Actual behavior

It always force opens and force focuses the conversations assigned MR.

Impact

Major degradation or frequent failure

Version or commit

0.0.41-nightly.20260916.1795

Environment

macOS 26.6

Logs or stack traces

Screenshots, recordings, or supporting files

No response

Workaround

No response

Start in apps/desktop by tracing the new MR auto-assign flow that opens or focuses the sidebar when a thread is opened. Reproduce with multiple conversations and MRs, including an already-open sidebar tab; done means the existing tab state is respected and the MR is not opened or focused in duplicate tabs.