I'm trying to filter all the labels as shown in help, with @, but does not work
Thank you for report, we'll look into it. This is an older feature, though which became a bit redundant now considering that you can see all your labels anytime on the "Labels" tab on the left.
I really saw this problem while testing !@ to filter tasks unlabeled
This feature is indeed deprecated and we've removed this syntax from the help page. As I've mentioned, you can see the list of your labels anytime on the left side of the screen.
ok. So is there no Possibility to make a filter that shows me all the tasks that are unlabeled?
No, labels can be managed on the left side menu. We may consider adding options to show non labeled tasks, but there is no way to do that now.
OK. I will vote or add this feature in VoteBox
Thank you very much for your patience. Are doing a good job :-)