Hi, I'm planning to change this to a 4-star (at least), after you read and responded to this, though!
This add-on seems to somehow stop Firefox from loading up pages on first launch, i.e. when I open Firefox, initially no pages load up, but when I use "Safe Mode" and then get back to "Normal" Firefox the problem is fixed. I am quite positive that the culprit is "UBO", as the problem disappears as soon as I disable the add-on.
Hope you can fix this.