====== Set Display Range of Axis ======
The normal way to change the display range of an axis is:
<code C++>
histogram->GetYaxis()->SetRangeUser(lower,upper);
</code>

but there are several situations where this fails. See below for help in these cases.

===== Y Axis of a normalized Histogram =====
Assume you have a histogram which has been normalized it with 
<code c++>
hist->SetNormFactor(1)
</code>
Your Y-axis will show values between 0 and 1. 
Trying to set the Y range using these values, eg. 
<code c++>SetRangeUser(0.01, 0.2)</code>
will fail however.
You still need to give the range in the original unnormalized units.

You can scale normalized units back with:
<code C++>
Double_t scaleY = hist->GetEntries()/hist->GetNormFactor();
hist->GetYaxis()->SetRangeUser(normalizedLower*scaleY,normalizedUppe*scaleY);
</code>

===== Y Axis of a THStack =====
Do not try to ''SetLimits'' or ''SetRangeUser'' of any histogram.
Instead use the following code:
<code c++>
THStack *hs = new THStack("hs","test stacked histograms");
hs->SetMinimum(0.);
hs->SetMaximum(10.);
</code>


===== X Axis of TGraph =====
If you have a TGraph, SetRangeUser will not work for the x axis.
It will not complain but also not do anything. Or not the thing you want.

You have to use SetLimits(), like:
<code C++>
TGraph* myGraph = new TGraph();
...
myGraph->GetXaxis()->SetLimits(lower,upper);
</code>