Bug 124620 Referenced Parameter icon should be invalid if the parameter in library is deleted
Description: Referenced parameter icon should be invalid if the source parameter in library is deleted. Steps to reproduce: 1.Create a library. Insert a report scalar parameter. 2.Create a report, use the above library. In the library explorer, pull the parameter to the data explorer view of report. 3.Open the library file, delete the parameter. Then reopen the report design file, the icon of parameter seems nothing happened. But if those operations happened in dataset, the icon of dataset in the report will be invalid. It is acceptable. Expected Result: The icon of referenced parameter should be invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DesignElementHandle.java
/**
	 * Determines if this element is editable or not. If the element comes from
	 * a library, it can not be edited in the report design.
	 * 
	 * @return true if it can be edited. false if it can't.
	 */
	public boolean canEdit( )
	{
		boolean flag = getElement( ).canEdit( );
		if ( !flag )
			return false;
		return !getModule( ).isReadOnly( );
	}
	/**
	 * Determines if the current element can be transformed to a template
	 * element. False will be returned if the element can not be dropped or the
	 * container of the current element can not contain the template element.
	 * 
	 * @return true if it can be transformed, otherwise false.
	 */
	public boolean canTransformToTemplate( )
	{
		boolean flag = getElement( ).canTransformToTemplate( getModule( ) );
		if ( !flag )
			return false;
		return !getModule( ).isReadOnly( );
	}
	/**
	 * Determines if the slot can contain an element with the type of
	 * <code>type</code>.