The link between the message annotation and the message link is not displayed and maybe at the heart of the problem - but basically if you drag the message annotation, an exception occurs in the log when it is dropped:

eclipse.buildId=I20100608-0911
java.version=1.6.0_18
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86, WS=gtk, NL=en_US
Framework arguments: -product org.eclipse.epp.package.jee.product
Command-line arguments: -os linux -ws gtk -arch x86 -product org.eclipse.epp.package.jee.product

Error
Wed Mar 09 16:21:10 GMT 2011

java.lang.NullPointerException
at org.jboss.bpmn2.editor.core.utils.AnchorUtil.reConnect(AnchorUtil.java:152)
at org.jboss.bpmn2.editor.core.features.DefaultBpmnMoveFeature.postMoveShape(DefaultBpmnMoveFeature.java:35)
at org.eclipse.graphiti.features.impl.DefaultMoveShapeFeature.moveShape(DefaultMoveShapeFeature.java:65)
at org.eclipse.graphiti.internal.command.MoveShapeFeatureCommandWithContext.execute(MoveShapeFeatureCommandWithContext.java:81)
at org.eclipse.graphiti.internal.command.CommandContainer.execute(CommandContainer.java:81)
at org.eclipse.graphiti.ui.internal.command.GefCommandWrapper.execute(GefCommandWrapper.java:51)
at org.eclipse.graphiti.ui.internal.editor.EmfOnGefCommand.execute(EmfOnGefCommand.java:58)
at org.eclipse.graphiti.internal.command.GFPreparableCommand2.doExecute(GFPreparableCommand2.java:37)
at org.eclipse.emf.transaction.RecordingCommand.execute(RecordingCommand.java:135)
at org.eclipse.emf.workspace.EMFCommandOperation.doExecute(EMFCommandOperation.java:119)
at org.eclipse.emf.workspace.AbstractEMFOperation.execute(AbstractEMFOperation.java:150)
at org.eclipse.core.commands.operations.DefaultOperationHistory.execute(DefaultOperationHistory.java:511)
at org.eclipse.emf.workspace.impl.WorkspaceCommandStackImpl.doExecute(WorkspaceCommandStackImpl.java:208)
at org.eclipse.emf.transaction.impl.AbstractTransactionalCommandStack.execute(AbstractTransactionalCommandStack.java:165)
at org.eclipse.graphiti.ui.internal.editor.GFWorkspaceCommandStackImpl.execute(GFWorkspaceCommandStackImpl.java:47)
at org.eclipse.emf.transaction.impl.AbstractTransactionalCommandStack.execute(AbstractTransactionalCommandStack.java:219)
at org.eclipse.graphiti.ui.internal.editor.GFWorkspaceCommandStackImpl.execute(GFWorkspaceCommandStackImpl.java:39)
at org.eclipse.graphiti.ui.internal.editor.GFCommandStack.execute(GFCommandStack.java:108)
at org.eclipse.gef.tools.AbstractTool.executeCommand(AbstractTool.java:425)
at org.eclipse.gef.tools.AbstractTool.executeCurrentCommand(AbstractTool.java:438)
at org.eclipse.gef.tools.DragEditPartsTracker.performDrag(DragEditPartsTracker.java:491)
at org.eclipse.gef.tools.DragEditPartsTracker.handleButtonUp(DragEditPartsTracker.java:346)
at org.eclipse.gef.tools.AbstractTool.mouseUp(AbstractTool.java:1201)
at org.eclipse.gef.tools.SelectionTool.mouseUp(SelectionTool.java:572)
at org.eclipse.gef.EditDomain.mouseUp(EditDomain.java:301)
at org.eclipse.gef.ui.parts.DomainEventDispatcher.dispatchMouseReleased(DomainEventDispatcher.java:380)
at org.eclipse.draw2d.LightweightSystem$EventHandler.mouseUp(LightweightSystem.java:548)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:213)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1258)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3552)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3171)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2629)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2593)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2427)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:670)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:663)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)