description:
exception is thrown out when click "sort by alphabetic" when the focus is in one of the text under "sort by group".

build number:
2.6.0.v20100303-0630

steps to reproduce:
1. new a report and open property editor->advanced.
2. click "sort by group" and put the focus in "image dpi" text.
3. click "sort by alphabetic".

expected result:
no exception.

actual result:
exception is thrown out.
error log:
org.eclipse.swt.swtexception: failed to execute runnable (org.eclipse.swt.swtexception: widget is disposed)
at org.eclipse.swt.swt.error(swt.java:4083)
at org.eclipse.swt.swt.error(swt.java:3998)
at org.eclipse.swt.widgets.synchronizer.runasyncmessages(synchronizer.java:137)
at org.eclipse.swt.widgets.display.runasyncmessages(display.java:3959)
at org.eclipse.swt.widgets.display.readanddispatch(display.java:3580)
at org.eclipse.ui.internal.workbench.runeventloop(workbench.java:2407)
at org.eclipse.ui.internal.workbench.runui(workbench.java:2371)
at org.eclipse.ui.internal.workbench.access$4(workbench.java:2220)
at org.eclipse.ui.internal.workbench$5.run(workbench.java:500)
at org.eclipse.core.databinding.observable.realm.runwithdefault(realm.java:332)
at org.eclipse.ui.internal.workbench.createandrunworkbench(workbench.java:493)
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:194)
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:367)
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:585)
at org.eclipse.equinox.launcher.main.invokeframework(main.java:611)
at org.eclipse.equinox.launcher.main.basicrun(main.java:566)
at org.eclipse.equinox.launcher.main.run(main.java:1363)
caused by: org.eclipse.swt.swtexception: widget is disposed
at org.eclipse.swt.swt.error(swt.java:4083)
at org.eclipse.swt.swt.error(swt.java:3998)
at org.eclipse.swt.swt.error(swt.java:3969)
at org.eclipse.swt.widgets.widget.error(widget.java:467)
at org.eclipse.swt.widgets.widget.checkwidget(widget.java:340)
at org.eclipse.swt.widgets.treeitem.gettext(treeitem.java:899)
at org.eclipse.swt.accessibility.accessible.get_accdescription(accessible.java:1986)
at org.eclipse.swt.accessibility.accessible$1.method12(accessible.java:134)
at org.eclipse.swt.internal.ole.win32.comobject.callback12(comobject.java:173)
at org.eclipse.swt.internal.win32.os.callwindowprocw(native method)
at org.eclipse.swt.internal.win32.os.callwindowproc(os.java:2341)
at org.eclipse.swt.widgets.tree.callwindowproc(tree.java:1530)
at org.eclipse.swt.widgets.control.windowproc(control.java:4052)
at org.eclipse.swt.widgets.tree.windowproc(tree.java:5838)
at org.eclipse.swt.widgets.display.windowproc(display.java:4731)
at org.eclipse.swt.internal.win32.os.sendmessagew(native method)
at org.eclipse.swt.internal.win32.os.sendmessage(os.java:3135)
at org.eclipse.swt.widgets.tree.removeall(tree.java:3942)
at org.eclipse.birt.report.designer.internal.ui.views.attributes.widget.advancepropertydescriptor$7.run(advancepropertydescriptor.java:753)
at org.eclipse.swt.widgets.runnablelock.run(runnablelock.java:35)
at org.eclipse.swt.widgets.synchronizer.runasyncmessages(synchronizer.java:134)
... 22 more
close it, can't reproduce the bug again on my machine and qa machine.