NPE after saving when opening a document 'twice'

1) go to a hippo:document
2) highlight document
3) click edit
4) click on the 'folder'
5) highlight document again
6) click edit (nothing happens)
7) go to editing pane, and click on save.

I know it is certainly not a 'likely' way to do, but just need to avoid NPE's, therefor, priority is set to high

java.lang.NullPointerException
at org.hippoecm.frontend.model.properties.JcrPropertyValueModel.load(JcrPropertyValueModel.java:221)
at org.hippoecm.frontend.model.properties.JcrPropertyValueModel.getObject(JcrPropertyValueModel.java:113)
at org.apache.wicket.Component.getModelObject(Component.java:1559)
at org.apache.wicket.Component.getModelObjectAsString(Component.java:1581)
at org.apache.wicket.markup.html.form.FormComponent.getModelValue(FormComponent.java:1284)
at org.apache.wicket.markup.html.form.FormComponent.getValue(FormComponent.java:797)
at org.apache.wicket.markup.html.form.TextField.onComponentTag(TextField.java:100)
at org.hippoecm.frontend.widgets.TextFieldWidget$1.onComponentTag(TextFieldWidget.java:37)
at org.apache.wicket.Component.renderComponent(Component.java:2452)
at org.apache.wicket.MarkupContainer.onRender(MarkupContainer.java:1411)
at org.apache.wicket.Component.render(Component.java:2318)
at org.apache.wicket.MarkupContainer.renderNext(MarkupContainer.java:1297)
at org.apache.wicket.MarkupContainer.renderComponentTagBody(MarkupContainer.java:1476)
at org.apache.wicket.MarkupContainer.renderAssociatedMarkup(MarkupContainer.java:639)
at org.apache.wicket.markup.html.panel.Panel.onComponentTagBody(Panel.java:112)
at org.apache.wicket.Component.renderComponent(Component.java:2481)
at org.apache.wicket.MarkupContainer.onRender(MarkupContainer.java:1411)