I am using resizables to display an object in a Gantt-chart like setup where each resizable object represents some subset of the overall range available. If you consider horizontal sizing only, the left and right edges of the parent are the min and max values and the resizable can represent any subset of that range by dragging the edges.

Initially I attempted to position the left/width of the resizable object using percentages like so:

<div class="package" id="pkg1" style="margin: 5px; padding: 20px; background-color: #eee; left: 15%; width: 40%;">
  <div style="float: left; background-color: #ccc; width: 20%;">Package #1</div>
  <div style="float: left; background-color: #f00; width: 80px;">$250.00</a></div>
</div>

The associated resizable call was:

$(".package").resizable({ handles: 'w, e', autohide: true, minWidth: 10, containment: 'parent'});

This results in bizarre behavior where the resizable is displayed properly at first. However, upon trying to drag either handle results in the left handle snapping back to the left edge of the parent. After that, it behaves properly.

If instead you use pixels:

<div class="package" id="pkg1" style="margin: 5px; padding: 20px; background-color: #eee; left: 167px; width: 236px;">
  <div style="float: left; background-color: #ccc; width: 20%;">Package #1</div>
  <div style="float: left; background-color: #f00; width: 80px;">$250.00</a></div>
</div>

It works as expected including the initial drag. It appears the percentage is miscalculated when the widget is instantiated.

Percentage-based support would be valuable in order to support fluid layouts.

I've confirmed this in both FF 2 and IE 6 on Windows XP.