A Horrible flaw ruins this for me! Rated 4 out of 5 stars

I am amending my previous glowing review for an update:
I absolutely LOVE this addon, everything about it is just what I need...and the way it lets you have multiple pages of groups arranged is just brilliant for someone who uses the net so often and visits a million and one sites a day. however!
Lately I noticed that, in my windows XP, whenever I loaded up FF (version 3.0x) the 'working in the background' icon that you usually see for a second or so when starting a large application or something, was startiung to show up all the time when firefox was running.
I went through a long process of elimination to discover what exactly was causing this 'working in the background' icon to be there and so I started a fresh profile in FF and one by one, added my addons, then removed them if they didn't show the same symptom.
As soon as speed dial was added...you guessed it: The problem was there right away.
And sure enough, in my usual FF profile, if I disable speed dial in addons prefs then on restarting the problem is no longer there.
I do not have to have the speed dial page opened for this to happen either. I think that speed dial is refreshing its pages, images in the background. There is the occasional error in the error console but, nothing of consequence. Seems to me the addon is just being a bit to busy in the background and, as such, is causing this highly irritating behaviour. apart from the irritation of never really seeing the default cursor/pointer when I am in firefox, it also seems to have a progressive slow-down effect, making FF sluggish eventually.
If the addon is disabled, everything is fine and dandy.
I have disabled every thumbnail in the addons page, so that every shortcut I made is loading an image locally, from my hard drive, instead of speed dial ever having to go visit the sites itself. I thought this would stop the problem but no change.
PLEASE LOOK INTO THIS and maybe you can work it out my author cos' for the moment I am going to consider trying another addon like yours. I will admit right now though - yours is by FAR the best one in its class so please see if you can at least make it an optional thing, to let speed dial actually work in the background (I reckon it is visiting the sites for some reason when it is started as I seen the odd error in the error console for a site I wasnt visiting at the time and yet it was a site I have as a shortcut in spee dial - so that tells me speed dial is for some reason checking the sites in the shortcuts?)
Anyway I wil live in hope that you can maybe give us an option to disable all dynamic, updating behaviour for the thumbnails/shortcuts. that would do it!

Thanks.

This review is for a previous version of the add-on (0.7.2.5).