Problem with Sortable

Hello, I have a problem with Sortable. I set some style to a sortable item. Let's say this:

<div style="border:1px solid red"></div>

But when I sort this item using sortable, it changes style to this:

<div style="border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-top-color: red; border-right-color: red; border-bottom-color: red; border-left-color: red; float: left; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid;"></div>

Do you have idea why is this happening ? Is there any way how to change this behaviour ?

Thank you very much,

Rudolf.