Bad Number of entries in Statistics box after histos substraction

From: David d'Enterria (enterria@in2p3.fr)
Date: Mon Aug 16 1999 - 00:53:32 MEST 

Hello developers,

I substract two histograms via:
TH1F *h_en_90deg_photon_no_cosm = new TH1F(*h_en_90deg_photon);
h_en_90deg_photon_no_cosm->Sumw2();
h_en_90deg_photon_no_cosm->Add(h_en_90deg_photon,h_en_90deg_cosmic,1,-1);

The number of entries of each histo is:
h_en_90deg_photon.Integral()
23119
h_en_90deg_cosmic.Integral()
439
h_en_90deg_photon_no_cosm.Integral()
22680

However when one draws this last histogram:
h_en_90deg_photon_no_cosm.Draw()

one reads in the statistics box:
Nent=23558        (namely, the SUM of the substracted histos ...)

This result is a little bit misleading ... Can you correct that ?

I'm using ROOT 2.22/10 on
uname -a:"Linux nanpc45.in2p3.fr 2.0.35 #1 Thu Jul 23 14:01:04 EDT 1998
i686 unknown

Thank you in advance,

David d'Enterria
¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬
Groupe Photons Subatech       http://www-subatech.in2p3.fr/~photons/
mailto:enterria@in2p3.fr      phone: +33.2.51.85.84.89
¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬
Grup Física Radiacions UAB    http://cc.uab.es/~iffr1/
mailto:d.enterria@cc.uab.es   phone: +3493.581.13.64

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