This problem should be fixed in the coming released version this week.
In case of TTrees/TNtuples in memory only (you did not open a file)
the memory buffers were deleted. One buffer contained 7983 events
in your example.
> b) I would like to get the fitparameters displayed in my canvas
> when I fit data points using TGraphErrors. I can display the
> data points with errors, can klick on the data points to
> get the fit panel, and I can perform a fit to the data points,
> but somehow I am not able to activate the 'fit parameter display'
> in my options menu. I there another way of getting the
> fit parameters displayed?
>
This option was not implemented so far. I have implemented the display
of the fit parameters for TGraph and TGraphErrors objects in the coming
version.
Rene Brun