Option to return spacewin as output arg from spacewin_gui

I think this would work as follows (pseudocode):

function [varargout] = spacewin_gui(W,NmVal)

if numel(varargout) > 0
    if NmVal.FigHandle
        varargout{1} = fig;
    else
        uiwait(close_button); % wait until the "close" button is pressed. Or "done" or something.
        varargout{1} = spacewin;
        delete(fig);
    end
end