com.vaadin.v7.data.Property$ReadOnlyException: nullcom.vaadin.v7.data.Property$ReadOnlyException: null at com.vaadin.v7.ui.AbstractField.setValue(AbstractField.java:470) ~[vaadin-compatibility-server-8.1.5.jar:8.1.5] at com.vaadin.v7.ui.AbstractField.setValue(AbstractField.java:445) ~[vaadin-compatibility-server-8.1.5.jar:8.1.5] at info.magnolia.ui.vaadin.richtext.MagnoliaRichTextField.changeVariables(MagnoliaRichTextField.java:84) ~[magnolia-ui-vaadin-common-widgets-5.6.3-SNAPSHOT.jar:5.6.3-SNAPSHOT] at com.vaadin.server.communication.ServerRpcHandler.changeVariables(ServerRpcHandler.java:626) ~[vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:471) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:414) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:274) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1568) [vaadin-server-8.1.5.jar:8.1.5] at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:381) [vaadin-server-8.1.5.jar:8.1.5] at info.magnolia.ui.admincentral.AdmincentralVaadinServlet.service(AdmincentralVaadinServlet.java:141) [magnolia-ui-admincentral-5.6.3-SNAPSHOT.jar:?] at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [servlet-api.jar:?]