Bug 177439 Need an easy way to determine default value for a dynamic parameter
Currently, I have to bring up the data set editor, preview the results in the data set and make a mental note of the value to use for a report parameter that depends on a data set. It would be nice to have a drop down on the default value field, such as <Select value> which when selected queries the data set and presents me with a list to select from.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
* 
	 */
	protected void checkBoxChange( Button checkBox, String key )
	{
		dirtyProperties.put( key, new Boolean( checkBox.getSelection( ) ) );
		if ( CHECKBOX_ISREQUIRED.equals( key ) )
		{
			if ( isStatic( ) )
			{
				makeUniqueAndValid( );
				refreshValueTable( );
			}
			if ( getSelectedDataType( ).equals( DesignChoiceConstants.PARAM_TYPE_STRING ) )
			{
				clearDefaultValueChooser( checkBox.getSelection( ) );
			}
			updateMessageLine( );
		}
	}
	private void clearDefaultValueChooser( boolean isChecked )
	{
		if ( isChecked )
		{
			clearDefaultValueText( );
			clearDefaultValueChooserSelections( );
		}
		else
		{
			if ( defaultValueChooser == null
					|| defaultValueChooser.getItemCount( ) > 0 )