Bug 146976 Save state of the report not correct.
Reproduce: 1) New a library "lib1", add a label "label1" 2) Publish "lib1" 3) New a report "report1", use "lib1" 4) Drag "lib1.label1" into "report1" 5) Go back to "lib1", drop "label1", save and publish again. 6) Go to "report1", refresh the libaray explorer and design. 7) Save "report1" 8) Now, we go back to "lib1" 9) Undo the previous "delete command", "label1" is added back. 10) Save "lib1", and re-publish. 11) Go to "report1", refresh the libaray explorer and design. 12) Save "report1" At this stage, "report1" is saved, but the dirty indicator(*) still displayed in the left side of the report name. I am testing on build N20060613
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/activity/ReadOnlyActivityStack.java
*/
	public boolean canUndo( )
	{
		return false;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.CommandStack#getUndoLabel()
	 */
	public String getUndoLabel( )
	{
		return null;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.CommandStack#undo()
	 */
	public void undo( )
	{
		throw new IllegalOperationException( MESSAGE );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.api.CommandStack#canRedo()
	 */
	public boolean canRedo( )
	{