Steps to reproduce:

1. Create a new project
2. Right-click on the Hierarchy window tab
3. Disable the Query Builder mode
4. Enter the following query "count\{p:a:assets}"
5. Enable the Query Builder mode
6. Observe that the query was converted to blocks, however "Add Query Block" button disappears and the Search field no longer accepts input text
7. Click on the "x" button to clear the query or alternatively, right-click on the added function query block and delete it via the context menu
8. Try interacting with the search field again

Actual results: Add Query Block remains missing and the search field does not accept input

Expected results: Search starts functioning again, once the unsupported query blocks are removed

Reproducible with versions: 6000.3.0a2, 6000.3.11f1, 6000.4.1f1, 6000.5.0b1, 6000.6.0a1

Can’t test with versions: 6000.0.71f1, 6000.3.0a1 (Hierarchy V2 not available)

Tested on (OS): macOS 26.3.1

Notes:

• Issue can be workaround by disabling and re-enabling the Query Builder mode