I believe I found a bug in the Draggable plugin. Maybe someone else can test and confirm, or perhaps provide a solution or workaround.. When I position a fixed div using the 'right' property, dragging left and right is very sluggish, in Firefox and Chrome. I never experience this sluggish movement in any other circumstance except when I use the 'right' property. If I simply replace the word 'right' with 'left', then that same div will drag normally in all directions. In IE it drags normally in all directions, regardless if you use 'right' or not. For example (with only applying a simple, $( "#div" ).draggable() , on the div),

No sluggishness at all in any browsers:

#nosluggishness
{
position: fixed;
width: 100px;
height: 100px;
left: 100px;
top: 50%;
margin-top: -50px;
background: red;
}

Sluggishness in FF+Chrome (but not IE):

#sluggishnessInFFAndChrome
{
position: fixed;
width: 100px;
height: 100px;
right: 100px;
top: 50%;
margin-top: -50px;
background: red;
}

Do you see what I'm talking about? Maybe it's not a bug in the actual Draggable plugin, maybe instead it's FF+Chrome not being fully compatible with the plugin? I don't know but it's driving me crazy.