How to permanently disable recent documents in Tasks widget on panel?
With right click on application in Tasks widget there are recent documents shown. And for every one application they need to be deleted separately.

Are you talking about the Task manager or actually about the Launcher? I see no "recent documents" when I right click in the Task Manager....

The Launcher can be configured not to show "often used" documents

My bad, I right click on the wrong application entry, sorry. And the answer: not that I know, other than not right clicking on it