Step sizes in ROOT's GL viewer

Hi All,

I was wondering if anyone knows how the step sizes in the ROOT GL viewer associated with up/down/left/right arrow keys are set. I'm finding that for one of the directions (up/down arrows) the step sizes are extremely large such that one press zoom the entire scene out of the viewable range. The left/right arrows work fine.

The outline of the procedure I'm using is:

TCanvas* c = new TCanvas("c","c",800,500); c->cd();
TPad* fPad = new TPad("fPad","3D pad",0,1,0,1); fPad->Draw();
fPad->cd();
// Draw several TPolyMarker3D, TPolyLine3D, etc. on fPad... fPad->GetViewer3D("ogl");

Thanks in advance for any help!

Cheers,
Mark

Mark Messier                                         messier_at_indiana.edu
Department of Physics            http://www.physics.indiana.edu/~messier
Indiana University                                 Phone: (812) 855-0236
Bloomington, IN 47405                                Fax: (812) 855-0440