[Gretl-users] side-by-side time series to panel conversion greyed out

Hi all, I'm having problems with the attached dataset, which holds annual regional GDP values for the German federal states (plus the German total). This is in time series format but I'd like to convert it to a panel structure with the relatively recent GUI feature of using several "side-by-side" time series. I have used this feature successfully in the past, but with this dataset the relevant option in the dialog following the choice of Data - Dataset structure - interpret as panel is not accessible, greyed out. When I don't have the time trend variable in the dataset, gretl even complains that the dataset cannot be turned into a panel at all. What's happening here? I guess I can work around this problem by using the script commands from section 4.5 of the guide (haven't tried yet), but that's suboptimal. thanks sven