Next question about custom fields

Hello,

i have made some custom fields.
now, when i search for tickets, it is not possible to show this as columns in the search result, because the custom fields are not shown in the “add column”.
But when i add the Queue on which the special field applies to in the search string, then the special field is listed in the “add column”??
How can i change, that the special field is always shown in the “add column” list?

RT version: 3.6.0