Bug 175766 Filter tab on a table is missing the Add buttons
There is no way to add/delete a filter on the table.
UI/org.eclipse.birt.report.designer.ui.views/src/org/eclipse/birt/report/designer/internal/ui/views/attributes/page/FormPage.java
deRegisterEventManager( );
	}
	public void addElementEvent( DesignElementHandle focus, NotificationEvent ev )
	{
		if ( checkControl( formSection ) )
			if ( formSection != null
					&& formSection.getFormControl( ) != null
					&& !formSection.getFormControl( )
							.getControl( )
							.isDisposed( ) )
				formSection.getFormControl( ).addElementEvent( focus, ev );
	}
	public void clear( )
	{
		if ( checkControl( formSection ) )
			formSection.getFormControl( ).clear( );
	}
	private boolean checkControl( FormSection form )
	{
		return form != null
				&& form.getFormControl( ) != null
				&& !form.getFormControl( ).getControl( ).isDisposed( );
	}
	public void postElementEvent( )
	{
		if ( checkControl( formSection ) )
			formSection.getFormControl( ).postElementEvent( );
	}
}