scrollbar for plot window

Binary package hint: qtiplot

I wish there is a scrollbar for the plot window so that I can view different parts of the plot. Usually when creating a new plot, the whole plot is shown in the plot window. But after some operations the plot somehow (how?) changes its shape and only a part of it can be seen in the plot window (see the attached picture). It would be convenient to have a plot window scrollbar so that one can see the whole plot. It would be even better if a button can restore the whole plot in the window.

Ubuntu used: 10.04
Qtiplot: 0.9.7.10