Error bands and tick marks


I am trying to draw error bands (TF1 functions) together with the fit function. Is there a feature to do this automatically? TGraphError supplies error bands, but these just connect the error points. In my case I am calculating the analytical error band for the fit function from the covariance matrix of the fit. Is there an implemented way to do this?

At the moment I am using a workaround which bringes me to the second problem that I have:
For the upper error band, the fit function and the lower error band I use a TF1 and draw it in a frame that I create via TCanvas::DrawFrame().
I set the FillStyle for the upper and lower error band to (1001) and the FillColor of the upper error band to some color, for the lower one to white. This way I get a colored error band and the fit function on top of it. Unfortunately this also draws the fill area over the axis tick marks. How can I get the tick marks in the foreground of the Frame? Is there a way to redraw them?

Thanks for any suggestions,