Navigation issue with shortcut key

Hi,

We disabled back button on wizard's first page and enabled back button on second page. When we navigate to second page (click Next) and then again come back (click Back) to first page. All works fine. (i.e. Back button is in disabled state)

But, the problem arises when shortcut keys are used that is hit Alt-B on second page and notice that Back button is in enabled state on the first page.

Steps to reproduce:
case 1:
1) Hit Alt-B on second page. (to simulate Back)
2) Notice on first page Back button is enabled (which was initially disabled and using mouse navigation it works fine)

case 2:
1) Hit Alt-B on second page. (to simulate Back)
2) Notice on first page Back button is enabled
3) Hit Alt-N or Alt-H or Alt-C nothing works.

Is this a bug? Or we are doing something wrong here.

Thanks,
Anurodh