gretl doesn't allow different datasets in same window unless you clear the current one or run multiple main windows. secondary window tabs for new data sets would be great. (like the tabs of internet browsers or something else like in excel...).
Personally I would probably also like this, but if I understand Allin correctly this would be a huge disruption of how gretl handles data internally, and in that sense it's problably not gonna happen. Although I have to admit that running separate gretl instances would be easier if the different sub-windows weren't freely floating around...
Anyway I think this is unrealistic --sorry-- and so I'm closing this.