In "Search" dialog box, there is an option "Drag a column header here to group by that column". It works good, but dragging column header back to table view (not header) causes whole column to disappear and there is no way to get it back ("Reset dialog boxes to default settings" doesn't do the job).
By accident I have found a workaround for it: you need to do do it for all headers (so table view is empty), and when you run search dialog box again, it's set to default view.
It shouldn't behave that way (in fact promis.e shows "X" sign as for forbidden operation, but allows me to do this stupid thing; so that's the task for developers) - but maybe someone will find that workaround useful.
08.11.12.137
Regards, Wojtek
Another way to reset that is to Rename the user application data folder. The "X" sign you see is probably for the removal of that field from the search box, but I agree that there is no easier way to get it back.
Yes, there is already a defect in the system to change that behavior, and a Tech Note to describe the process we recommend to resolve it if it happens, which k_obsr mentioned: Columns missing from dialogs, error messages