Custom field in "new-gen" project not usable in Project Explorer

[me]

In a "new-gen" Project I added an new textfield to the issue-type "tasks" named "Meeting".

It is not possible to use this new field in the project-explorer.
- in the simple view I can find "Meeting" in the list but is´s grayed out with a red exlamationmark in the end.
- in the extended jql view I get the errormessage:
  "the operator '='  is not supported by the field  'Meeting' "
   for the 
   jql "project = "CF" AND issuetype = Task and Meeting = "something""

Whats wrong?

[Angélica Luz · Accepted solution]

Hi Michael,

Next-gen are independent projects, so the fields created on each project cannot be used on Classic projects.
Also, the reason why the JQL is not working is that the only supported operators for text are: 

If you have any other question, please let us know.

Regards,
Angélica