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 ( StringUtil.isBlank( value ) )
			{
				return ERROR_MSG_CANNOT_BE_BLANK;
			}
		}
		try
		{
			getValue( value );
		}
		catch ( BirtException e )
		{
			return ERROR_MSG_MISMATCH_DATA_TYPE;
		}
		return null;
	}
	private boolean isEqual( String value1, String value2 )
	{
		Object v1 = null;
		Object v2 = null;
		try
		{
			v1 = getValue( value1 );
			v2 = getValue( value2 );
		}
		catch ( BirtException e )
		{
		}
		if ( v1 == null )
		{