Bug 153523 OK button in parameter dialog is enabled without default value in combo-box
Description: OK button in parameter dialog is enabled without default value in combo-box Steps to reproduce: 1. New a report parameter, combo-box. 2. Click New button, input abc as value, click OK 3. Set abc as default value and close Edit Parameter dialog. 4. New a data source and dataset 5. Edit the parameter, remove abc value and import values from dataset Expected result: OK button is disabled for there is no default value. Actual result: OK button is enabled.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
}
	
	private void updateMessageLine( )
	{
		String errorMessage = validateName( );
		if ( errorMessage == null )
		{
			if ( !isStatic( )
					&& columnChooser != null
					&& columnChooser.getItemCount( ) == 0 )
			{
				errorMessage = ERROR_MSG_NO_AVAILABLE_COLUMN;
			}
			else if ( defaultValue == null
					&& ( PARAM_CONTROL_COMBO.equals( getSelectedControlType( ) ) || DesignChoiceConstants.PARAM_CONTROL_RADIO_BUTTON.equals( getSelectedControlType( ) ) ) )
			{
				
				errorMessage = ERROR_MSG_NO_DEFAULT_VALUE;
			}
		}
		if ( errorMessage != null )
		{
			errorMessageLine.setText( errorMessage );
			errorMessageLine.setImage( ERROR_ICON );
		}
		else
		{
			errorMessageLine.setText( "" ); 
			errorMessageLine.setImage( null );
		}