"Discard changes" throws Wicket stacktrace

• Edit a document.
• Change some content.
• Do NOT press save, but close the tab instead.
• A dialog pops up asking "You have possibly changes in this node or child nodes. Cancel Save Discard changes and close".

Clicking on "Discard changes and close" throws a Wicket RuntimeException:
java.lang.NullPointerException
at org.hippoecm.frontend.model.WorkflowsModel.iterator(WorkflowsModel.java:113)
at org.hippoecm.frontend.plugin.workflow.WorkflowsPlugin$1.getItemModels(WorkflowsPlugin.java:88)

Clicking "Save" throws a Wicket RuntimeException:
java.lang.NullPointerException
at org.hippoecm.frontend.model.WorkflowsModel.getWorkflowDescriptor(WorkflowsModel.java:103)
at org.hippoecm.frontend.plugins.reviewedactions.FullReviewedActionsWorkflowPlugin.receive(FullReviewedActionsWorkflowPlugin.java:122)

The only other option: "Cancel" works fine :-/