Enabling Google Docs paste functionality with Firefox 3

I was having trouble pasting content into Google Docs using Firefox, something that used to work for me.

There must have been a Firefox update that stopped it working because I certainly didn't change anything.

Anyway, I did the following to get it working again;

Tools menu
Options
Content tab
Enable Javascript (should be checked)
Advanced button on same line
Uncheck "Disable or replace context menus"