Why is Firefox missing the border on some HTML tables

Question

I am using Firefox 3.5.7 and I have the same CSS used in multiple HTML tables, but there are some examples where parts of the borders are not shown.

What makes no sens

Answer 1

Maybe you've zoomed in/out a bit. This can happen either accidently or knowingly when you do Ctrl+Scrollwheel. Maybe it isn't completely resetted to zoom level zero. This mis-rendering behaviour is then recognizeable at some websites, also here at SO.

To fix this, just hit Ctrl+0 or do View > Zoom > Reset to reset the zoom level to default.

This is Firefox/Gecko bug 410959. This affects tables with border-collapse:collapse. It's from 2008 and there's no real progress on it, so you'll probably need to find a workaround. One way is using border-collapse:separate and fiddling with borders on a per-cell basis.