Thanks for looking at this for the next version.
> the quick way to clear the selection is to tick "All fields"
I thought that might be the way to reset it, but when you re-choose Search Specific Fields -> 'activate', the current selection is not reset. The only way I've found to deselect the items in a 'specific search' is to do it one field at a time.
Personally I'd be content with deselecting one field at a time if the menu stayed open. But a one-click way of clearing the selection completely would also be useful.