MultiSelect=false is not respected when opening a Search window.

Steps to reproduce:

1. Open attached project.
2. Open the test Search window with the menu "Tests/Open Search No MultiSelect".
3. Search should open with two material results.
4. Try to multi select them using Ctrl+Click and Shift+Click.

Actual results: 

The items are multi selected.

Expected results: 

The items should not be multi selectable.

Reproducible with versions: 6000.2.0a7, 6000.1.X, 6000.0.X

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): Windows 11

Notes:

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