Bug 168026 Still use the existing data binding even though the aggregate is different
I had a table in which a data binding which aggregates on a group. When I insert a new data item in the report, although the expressions are same, it aggregates on All, then it refered to the existing data binding. The expected behavior would be a new data binding is created with different aggregates.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ScalarParameterHandle.java
* @see org.eclipse.birt.report.model.api.elements.DesignChoiceConstants
	 */
	public void setDataType( String type ) throws SemanticException
	{
		setStringProperty( DATA_TYPE_PROP, type );
	}
	/**
	 * Returns the default value of the parameter. The default value can be an
	 * expression, but cannot reference any other parameters.
	 * 
	 * @return the default value
	 */
	public String getDefaultValue( )
	{
		return getStringProperty( DEFAULT_VALUE_PROP );
	}
	/**
	 * Sets the default value of the parameter. The default value can be an
	 * expression, but cannot reference any other parameters.
	 * 
	 * @param defaultValue
	 *            the default value for the parameter
	 * @throws SemanticException
	 *             if the property is locked.
	 */
	public void setDefaultValue( String defaultValue ) throws SemanticException
	{
		setProperty( DEFAULT_VALUE_PROP, defaultValue );
	}
	/**