[ https://issues.jboss.org/browse/DROOLS-2458?page=com.atlassian.jira.plugi... ] Michael Anstis edited comment on DROOLS-2458 at 4/9/18 11:04 AM: ----------------------------------------------------------------- Stack trace is this:- {code} LgI_g$ (FormPropertiesWidget.java:150) TgI_g$ (FormPropertiesWidget.java:79) vhI_g$ (FormsCanvasSessionHandler.java:213) uhI_g$ (FormsCanvasSessionHandler.java:205) giI_g$ (FormsCanvasSessionHandler.java:256) TVF_g$ (AbstractCanvasHandler.java:363) qeG_g$ (DeleteCanvasConnectorCommand.java:51) <-- context.notifyCanvasElementUpdated(target) -- see below. peG_g$ (DeleteCanvasConnectorCommand.java:40) ... {code} The {{DeleteCanvasConnectorCommand}} above looks like this:- {code} public class DeleteCanvasConnectorCommand extends AbstractCanvasCommand { ... @Override public CommandResult<CanvasViolation> execute(final AbstractCanvasHandler context) { if (!checkShapeNotNull(context, candidate.getUUID())) { //it is already not present on canvas return buildResult(); } context.deregister(candidate); if (null != source) { context.notifyCanvasElementUpdated(source); } if (null != target) { context.notifyCanvasElementUpdated(target); <-- BUT target has been deleted. } return buildResult(); } {code} The applicable part of {{FormPropertiesWidget}} is:- {code} public class FormPropertiesWidget implements IsElement, FormPropertiesWidgetView.Presenter { ... private void show(final String graphUuid, final Element<? extends Definition<?>> element, final Command callback) { final String uuid = element.getUUID(); <-- element is null here. {code} So the issue is that the Properties Panel is trying to be updated for a non-existence node. was (Author: manstis): Stack trace is this:- {code} LgI_g$ (FormPropertiesWidget.java:150) TgI_g$ (FormPropertiesWidget.java:79) vhI_g$ (FormsCanvasSessionHandler.java:213) uhI_g$ (FormsCanvasSessionHandler.java:205) giI_g$ (FormsCanvasSessionHandler.java:256) TVF_g$ (AbstractCanvasHandler.java:363) qeG_g$ (DeleteCanvasConnectorCommand.java:51) <-- context.notifyCanvasElementUpdated(target) -- see below. peG_g$ (DeleteCanvasConnectorCommand.java:40) ... {code} The {{DeleteCanvasConnectorCommand}} above looks like this:- {code} public class DeleteCanvasConnectorCommand extends AbstractCanvasCommand { ... @Override public CommandResult<CanvasViolation> execute(final AbstractCanvasHandler context) { if (!checkShapeNotNull(context, candidate.getUUID())) { //it is already not present on canvas return buildResult(); } context.deregister(candidate); if (null != source) { context.notifyCanvasElementUpdated(source); } if (null != target) { context.notifyCanvasElementUpdated(target); <-- BUT target has been deleted. } return buildResult(); } {code} So the issue is that the Properties Panel is trying to be updated for a non-existence node. -- This message was sent by Atlassian JIRA (v7.5.0#75005)