Table/Queue Properties: Not able to add Search Fields when selected SOSL and switched to Client Side

Table / Queue Filters & Search Properties:
When you select the checkbox “Use SOSL to improve search performance”, then change the search method to client, in the background SOSL is still selected and you are not able to add fields to search on.

You have to change the search method again to Server, deselect SOSL, change search method back to client and now you are able to add fields.