Scrolling code boxes?

[Graycode]

Thank you JJoe for mentioning different Firefox results! I had reviewed it with versions 2.0.0.20, 3.0.5, and a portable version of 3.0.10.

But this PC I'm on now is probably the quirky one. It's Win98SE with a little open-source package called KernelEx that enables newer Firefox and most other softwares to install & run on the old OS. What I'm seeing is probably caused by a KernelEx custom GDI extension interacting with Firefox. After all, for quite some time "Firefox can't be installed or run in Win9x". Some people, like me, are saving up their common-sense for a future day when we might need to use some.

Sorry for any confusion. Unless others are missing a scroll bar, I'm happy with being the 'quirk' instead of Firefox.