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
{
			if ( !loading
					|| ( ( inputParameter.getCategory( ) == null && inputParameter.getPattern( ) == null ) ) )
			{
				if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( getSelectedDataType( ) ) )
				{
					formatCategroy = choiceSet.findChoice( DesignChoiceConstants.STRING_FORMAT_TYPE_UNFORMATTED )
							.getName( );
				}
				else if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
				{
					formatCategroy = choiceSet.findChoice( DesignChoiceConstants.DATETIEM_FORMAT_TYPE_UNFORMATTED )
							.getName( );
				}
				else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( getSelectedDataType( ) )
						|| DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( getSelectedDataType( ) ) )
				{
					formatCategroy = choiceSet.findChoice( DesignChoiceConstants.NUMBER_FORMAT_TYPE_UNFORMATTED )
							.getName( );
				}
				formatPattern = null;
			}
			else
			{
				formatCategroy = inputParameter.getCategory( );
				if ( formatCategroy == null )
				{
					formatCategroy = DesignChoiceConstants.STRING_FORMAT_TYPE_UNFORMATTED;
				}
				formatPattern = inputParameter.getPattern( );