Sometimes 2D data objects are very similar to each other, or the user opened the same data twice in
a single data view.
In this case, the shift spectra function might have been applied to separate overlaying 2D data objects. You can
see it from the y-axis legend, if data is shifted. In this case, neither numbers nor a unit are shown on the y-axis. This function is only available,
if multiple 2D data objects are merged in one data view and if they have been previously shifted. Unshifting can
be applied multiple times in order to decrease the distance until the original proportions are reached.