Well, dang! No mouse at all
Real Administrators don't use a mouse ;-D
As of version 188.8.131.524 (released Friday 23/5/08), you CAN use the tab key to move from field to field ...
This is only workaround - not final, ergonomic solution.
In case of displaying dozens of alerts to confirm and at each user should press Tab key many times then there is not only problem of pressing Tab key hundreds times, but also situations when user press Tab one time too much and pressing Enter confirm other action that he wants.
From UI ergonomic and usability point of view (and of course Windows conventions) buttons should have shortcuts like Alt-A for "Allow", Alt-O for "OK", Alt-C for "Cancel", Alt-R for "Remember...", etc. and global Enter to "OK" and Esc to "Cancel" whole dialog (except when only "Allow" and "Block" buttons are displayed; I think that in this situation only Esc should be mapped to "Block", but Enter shouldn't be mapped to "Allow").
Bad, UI programmers. Bad.
Yeah, I agree, but fortunately we (users) can point out this bugs - and programmers (hopefully) can fix this. :-)