The different behaviour in case of create new or edit screen is not working for transition screen

[gvidali]

I have a behaviour so that its code works only in case of creating a new issue but not  when editing it.

That works great with below code:

if (getActionName() == null) { // null = edit issue
return // not the initial action, so don't set default values
}

That problem appears when I set a workflow transition to make the edit screen popup.

In that case the behaviour starts as it was a new issue.

Is there a problem in the getactionname code ?