Sortable: incorrectly considers hidden elements as the clone element

[michalm]

Was recently working on a project when i came across some weird behaviour with draggables connected to sortables.

A simple demo is included. 5px border is to make the bug more visible.

What to look for:

1. The draggable is losing its size, watch for the floating border.
   
2. Dragging to the first column causes a second placeholder with size zero to appear in 'random' placec in the same sortable.

Fix: Disabling the hidden sortables. In the demo: $(".sortable:hidden").sortable('disable');

Comments: Static sizing the elements fixes problem 2, but not 1.

[michalm]

Bug demo

[michalm]

Tested in IE 8, Firefox 3.5.5, Chrome 3.0.195.38

[mikesherov]

confirmed in chrome 22: ​http://jsfiddle.net/ExbdP/2/

to reproduce:

1. drag "drag me down" down to the first list and drop.
2. Notice that the element that gets added doesn't contain the text "drag me down".
3. Notice that while dragging, the text "drag me down" is multiline.

the problem goes away when the last line is uncommented.