Sometimes, when adding a new dataset to be plotted in the active graph window
(through Layer n dialog box->Plot Association Button->>'Select Columns for Plotting' dialog box opens) all I hear is a BEEP when pressing the add-button and thus I can't add the datasets displayed in the Column list boxes to the plotting list box. How come? Why isn't there a short error message explaining what origin "thinks" is wrong. This beeping is very frustrating.

I just figured that it always occurs when theres already a plot association with
the same y-column as the new plot. Try:
i.e. when theres already
data_1:A(X),C(Y)
you won't be able to add
data_1:B(X),C(Y)
There can be only one of them.

Thanks for any help.
Cheers
Daniel Kabs

Thanks for giving me advice.
I prefer to workaround using your first
method, copying the relevant Y column to a new one.

But quite frankly, I consider this
behaviour a bug which is based on the
naming of datasets in the LayerContentsList
(see Layer n dialog box).

Is this limited functionality removed
in Origin 5.0?