Selected users are buried in alphabetical order in filter dropdowns

Description

In user filter dropdowns such as “Assigned to…”, “Added by…”, and “Closed by…”, selected users remain mixed with unselected users in alphabetical order. This makes it difficult to quickly see and manage the current selections, especially when many users are present.

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Steps to reproduce

1. Open any board
2. Click on the “Assigned to…” filter
3. Select one or more users
4. Observe the order of items in the dropdown

Repeat the same steps for:

• “Added by…”
• “Closed by…”

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Expected behavior

• Selected users should appear at the top of the dropdown (sorted alphabetically among themselves)
• Unselected users should appear below (also sorted alphabetically)
• Special options such as “No one” should remain pinned at the very top

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Actual behavior

Selected users remain buried in the full alphabetical list and are hard to find once selected.

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Impact

When many users exist, it becomes difficult to:

• See which filters are currently active
• Quickly unselect users
• Manage multiple selections efficiently