Bug 166315 Combo box doesn't allow blank when set string type in parameter editor
Combo box doesn't allow blank when set string type in parameter editor Steps to reproduce: 1.New a parameter, display type is Combo Box 2.Select data type as String Expected result: "Allow blank values" is enable. Actual result: "Allow blank values" is gray and can't be checked.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
private void changeDataType( )
	{
		String type = getSelectedDataType( );
		if ( type.equals( lastDataType ) )
		{
			return;
		}
		if ( buildControlTypeList( type ) )
		{
			changeControlType( );
		}
		lastDataType = type;
		initFormatField( );
		if ( isStatic( ) )
		{
			makeUniqueAndValid( );
			refreshValueTable( );
		}
		else
		{
			refreshColumns( true );
		}
		updateMessageLine( );
	}
	private boolean buildControlTypeList( String type )
	{
		String[] choices;
		if ( isStatic( ) )
		{
			if ( DesignChoiceConstants.PARAM_TYPE_BOOLEAN.equals( type ) )