After several days I posted this, the blinking cursor ceased to appear on my Firefox (2.0.0.6) on Ubuntu Feisty. So I no longer have this problem. (Well, having the cursor was sometimes useful to know and determine which text to copy, but having functional Page Up/Page Dn etc. seems to be better... I don't know if I can have both)
Sorry for not updating.
After several days I posted this, the blinking cursor ceased to appear on my Firefox (2.0.0.6) on Ubuntu Feisty. So I no longer have this problem. (Well, having the cursor was sometimes useful to know and determine which text to copy, but having functional Page Up/Page Dn etc. seems to be better... I don't know if I can have both)