JOE should display a hint that existing job chain nodes with jobs have to be removed before a "nested job chain" can be configured

Starting Situation

• If you configure a job chain then you can assign either jobs to its nodes or job chains within nested job chain. You cannot mix both modes.
• We assume you have configured a job chain with jobs in one or more job chain nodes. If you click to "Nested Job Chains" in the same job chain then you get a form which doesn't work because this job chain has already a job in a node.

Desired Behavior

• JOE should display a hint that existing job chain nodes with jobs have to be removed before a "nested job chain" can be configured.

Maintainer Notes

• This feature request is valid as long as JS-210 is not available.