Last thumb not showing on product page

[St055]

Hello,

 

I noticed that the last thumb under product picture is not showing when there is a lot of thumbs. I've searched and found that on the container <ul> of the thmb list, there is a "style" added automaticaly with the width size to 970px. If I increase it to 973, the thumb (who was hidden) appears...

<ul id="thumbs_list_frame" style="width: 970px;">

Where can I find this 970px value? I can't find it to modify it...

Thanks

 

PS 1.6.0.5 / theme default bootstrap

 

An example: http://www.reef-guardian.com/boutique/fr/ecumeur-interne/1049-bubble-king-supermarin-300-rd3-speedy.html