description:
exception thrown out when click to fold embedded images node in outline

build:
2.6.0.v20100521-0630

steps to reproduce:
1. new a report
2. insert an embedded image
3. click embedded images node in outline

actual result:
exception thrown out

errorlog:
java.lang.classcastexception: org.eclipse.birt.report.model.api.embeddedimagehandle cannot be cast to org.eclipse.birt.report.model.api.designelementhandle
	at org.eclipse.birt.report.designer.internal.ui.views.libraryelementimagedecorator.getelementflag(libraryelementimagedecorator.java:76)
	at org.eclipse.birt.report.designer.internal.ui.views.libraryelementimagedecorator.decorateimage(libraryelementimagedecorator.java:37)
	at org.eclipse.birt.report.designer.internal.ui.views.defaultnodeprovider.decorateimage(defaultnodeprovider.java:333)
	at org.eclipse.birt.report.designer.internal.ui.views.defaultnodeprovider.getnodeicon(defaultnodeprovider.java:326)
	at org.eclipse.birt.report.designer.internal.ui.views.viewstreeprovider.getimage(viewstreeprovider.java:128)
	at org.eclipse.jface.viewers.wrappedviewerlabelprovider.getimage(wrappedviewerlabelprovider.java:117)
	at org.eclipse.jface.viewers.wrappedviewerlabelprovider.update(wrappedviewerlabelprovider.java:165)
	at org.eclipse.jface.viewers.viewercolumn.refresh(viewercolumn.java:152)
	at org.eclipse.jface.viewers.abstracttreeviewer.doupdateitem(abstracttreeviewer.java:934)
	at org.eclipse.jface.viewers.abstracttreeviewer$updateitemsaferunnable.run(abstracttreeviewer.java:102)
	at org.eclipse.core.runtime.saferunner.run(saferunner.java:42)
	at org.eclipse.ui.internal.jfaceutil$1.run(jfaceutil.java:49)
	at org.eclipse.jface.util.saferunnable.run(saferunnable.java:175)
	at org.eclipse.jface.viewers.abstracttreeviewer.doupdateitem(abstracttreeviewer.java:1014)
	at org.eclipse.jface.viewers.structuredviewer$updateitemsaferunnable.run(structuredviewer.java:481)
	at org.eclipse.core.runtime.saferunner.run(saferunner.java:42)
	at org.eclipse.ui.internal.jfaceutil$1.run(jfaceutil.java:49)
	at org.eclipse.jface.util.saferunnable.run(saferunnable.java:175)
	at org.eclipse.jface.viewers.structuredviewer.updateitem(structuredviewer.java:2141)
	at org.eclipse.jface.viewers.abstracttreeviewer.createtreeitem(abstracttreeviewer.java:829)
	at org.eclipse.jface.viewers.abstracttreeviewer$1.run(abstracttreeviewer.java:804)
	at org.eclipse.swt.custom.busyindicator.showwhile(busyindicator.java:70)
	at org.eclipse.jface.viewers.abstracttreeviewer.createchildren(abstracttreeviewer.java:778)
	at org.eclipse.jface.viewers.treeviewer.createchildren(treeviewer.java:644)
	at org.eclipse.jface.viewers.abstracttreeviewer.createchildren(abstracttreeviewer.java:749)
	at org.eclipse.jface.viewers.abstracttreeviewer.handletreeexpand(abstracttreeviewer.java:1444)
	at org.eclipse.jface.viewers.treeviewer.handletreeexpand(treeviewer.java:952)
	at org.eclipse.jface.viewers.abstracttreeviewer$4.treeexpanded(abstracttreeviewer.java:1455)
	at org.eclipse.swt.widgets.typedlistener.handleevent(typedlistener.java:132)
	at org.eclipse.swt.widgets.eventtable.sendevent(eventtable.java:84)
	at org.eclipse.swt.widgets.widget.sendevent(widget.java:1052)
	at org.eclipse.swt.widgets.widget.sendevent(widget.java:1076)
	at org.eclipse.swt.widgets.widget.sendevent(widget.java:1061)
	at org.eclipse.swt.widgets.tree.wmnotifychild(tree.java:7408)
	at org.eclipse.swt.widgets.control.wmnotify(control.java:5095)
	at org.eclipse.swt.widgets.composite.wmnotify(composite.java:1887)
	at org.eclipse.swt.widgets.control.wm_notify(control.java:4725)
	at org.eclipse.swt.widgets.control.windowproc(control.java:4214)
	at org.eclipse.swt.widgets.display.windowproc(display.java:4873)
	at org.eclipse.swt.internal.win32.os.callwindowprocw(native method)
	at org.eclipse.swt.internal.win32.os.callwindowproc(os.java:2362)
	at org.eclipse.swt.widgets.tree.callwindowproc(tree.java:1536)
	at org.eclipse.swt.widgets.tree.wm_lbuttondown(tree.java:6303)
	at org.eclipse.swt.widgets.control.windowproc(control.java:4194)
	at org.eclipse.swt.widgets.tree.windowproc(tree.java:5844)
	at org.eclipse.swt.widgets.display.windowproc(display.java:4886)
	at org.eclipse.swt.internal.win32.os.dispatchmessagew(native method)
	at org.eclipse.swt.internal.win32.os.dispatchmessage(os.java:2459)
	at org.eclipse.swt.widgets.display.readanddispatch(display.java:3655)
	at org.eclipse.ui.internal.workbench.runeventloop(workbench.java:2624)
	at org.eclipse.ui.internal.workbench.runui(workbench.java:2588)
	at org.eclipse.ui.internal.workbench.access$4(workbench.java:2422)
	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:39)
	at sun.reflect.delegatingmethodaccessorimpl.invoke(delegatingmethodaccessorimpl.java:25)
	at java.lang.reflect.method.invoke(method.java:597)
	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)
fixed.
verify the bug on build <2.6.0.v20100525-0630>