725149 - Setting position:relative on td can cause out-of-sequence dragenter events

Status: UNCONFIRMED

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Nathan Vander Wilt]

Attachment: dragdropeventing.html

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/534.53.11 (KHTML, like Gecko) Version/5.1.3 Safari/534.53.10

Steps to reproduce:

In a dragenter handler for a <td>, I set a class that happened to match a style rule including { position:relative }.


Actual results:

After this style rule is applied, Firefox seems to reset its event algorithm and forget that it already sent a dragenter event to the current target. This causes:
- a second dragenter event to be sent, if the current target has not changed
- if the current target is changed to a child element, it receives a dragenter event WITHOUT the parent element subsequently receiving a dragleave event.

See attached test case.


Expected results:

According to http://dev.w3.org/html5/spec/dnd.html the dragenter event should not be fired unless the current target element changes. Also, if a dragenter event is fired on a new current target element, the previous target element must receive a dragleave event.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Changing "position" recreates the CSS boxes, so does in fact change current event targets, sorta...