FF: Cannot scroll sideways

I have the latest version of Firfox, and I find that I cannot scroll
sideways -- or maybe I should say, the browser fails to recognize when a
page is too wide to be viewed without scrolling, and so the sideways
scrollbar never appears, so that I cannot see the whole page. I'm using 800
x 600 resolution, so it happens fairly often.

Could I have somehow turned off this useful feature?

Thanks for any thoughts or tips on this.

 

are you using the default theme?

--
Peeves That Your Dog Has About You . . . A Message From Your Dog:

Any haircut that involves bows or ribbons. Now you know why we chew
your stuff up when you're not home.

The sleight of hand, fake fetch throw. You fooled a dog! Whoooo
hoooooooo! What a proud moment for the top of the food chain.

Taking me to the vet for "the big snip", then acting surprised when I
freak out every time we go back!

.. . . to be continued

 

Thanks for the reply.

Yes, I am using the default theme.