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
String type = getSelectedControlType( );
			if ( !type.equals( lastControlType ) )
			{
				if ( DesignChoiceConstants.PARAM_CONTROL_CHECK_BOX.equals( type ) )
				{
					clearArea( valueArea );
					switchToCheckBox( );
				}
				else if ( PARAM_CONTROL_COMBO.equals( type )
						|| PARAM_CONTROL_LIST.equals( type )
						|| DesignChoiceConstants.PARAM_CONTROL_RADIO_BUTTON.equals( type ) )
				{
					
					if ( !PARAM_CONTROL_COMBO.equals( lastControlType )
							&& !PARAM_CONTROL_LIST.equals( lastControlType )
							&& !DesignChoiceConstants.PARAM_CONTROL_RADIO_BUTTON.equals( lastControlType ) )
					{
						clearArea( valueArea );
						switchToList( );
					}
				}
				else if ( DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( type ) )
				{
					clearArea( valueArea );
					switchToText( );
				}
				valueArea.layout( );
				initValueArea( );
				lastControlType = type;
			}