However, the typical use cases are to prompt the user that they should be entering another field depending on some condition, or to hide a field for clarity’s sake. In these cases, the user is better off with behaviours, and no worse off than they were without them.
If a behaviour makes a field read-only, the issue history can also reveal if that rule has been subverted.
Another side effect is that behaviours can't override other server-side validation rules, such as field configurations and workflow validators. For example, if you have a field configuration that specifies a field is required, a behaviour can't override that requirement. You can however, take a non-required field and make it required.
There is currently no support for bulk edits.
The field behaviours are retrieved from the server after the form has loaded in the browser. This may cause a delay in the styling being applied.
Multiple behaviours on the same field
It is possible to apply multiple behaviours in overlapping contexts. For example, you may have a behaviour that is mapped to one project and all issue types, then another behaviour that is mapped to all projects and one particular issue type.
Normally, this is fine as all applicable behaviours are applied in any given context. However, if both behaviours try to manipulate the same field, it’s possible for them to contradict each other. For example, if one behaviour tries to set the field to be read-only, but the other sets the field to be writeable, only one can win. If both behaviours set the field’s value to something specific, only one is applied.
If a behaviour appears to be working inconsistently, this is a likely cause.
It may be helpful in these circumstances to use one server-side behaviour for that field. You can map it to every applicable context, then provide some detailed logic specifying in one place what ought to happen in which circumstances. See Scripted Conditions for some sample code that you can re-purpose inside a behaviour.
Behaviours function on the Create Issue, Update/Edit Issue, Assign Issue, and Workflow Transition screens.
On the View Issue screen, trying to edit a field with a behaviour launches the Edit Issue screen, instead of the normal inline editor.
Behaviours do not work on the Move Issue screen. They also do not work for any bulk issue operations, or any issue edits that bypass the UI such as the REST API and other ScriptRunner scripts.
If you use a behaviour to link to other projects, the user interacting with the behaviour needs the appropriate permissions in those projects to do whatever it is you are having them do. For example, if you create a behaviour that allows a user to link to issues, that user must have the Link Issues permission in the other projects.