Multi-selection ListBox widgets

[ktritz]

The ListBox widgets are multi-selection, which doesn't make sense for many of the choices (e.g. abund choice, line ratio, etc.), . There should be a keyword passed when it makes sense to activate multi-selection.

[kdere]

Yes, you are right. However, for line ratios, if two lines are blended, you probably want to have the opportunity for multiple choices. For abundances, only one choice is appropriate