In LiveCycle ES3 (and SP1) Workbench, you could encounter this error when attempting to view the participant’s property editor in the Multiple Assign Task service when attempting to provide a list of Users via a process:
If you look at the Workbench .log located here: C:\Users\%UserName%\Workbench 10\.metadata\.log, you should see a similar message as below:
!ENTRY com.adobe.workflow.editor 4 0 2012-09-10 17:12:38.588
!MESSAGE Failed to load/render Property Editor
java.lang.RuntimeException: java.lang.ClassCastException: java.lang.String cannot be cast to com.adobe.livecycle.userlist.impl.UserlistThis error is not thrown when performing the same steps in ES 2.5.
This issue can be resolved by applying a quickfix for Workbench: 10.0.3-WKB-001 on top of SP1. The associated bug# is 3328833. Please contact Enterprise Support for the availability of this patch if you run into this problem attempting to use the Multiple Assign Task in Workbench.
After the patch is installed, and you click on the particpants property editor, you should see the editor as follows: