732635 - Transition does not fire on an item that has fixed positioning unless width is specified in script.

Status: RESOLVED INCOMPLETE

(Core :: CSS Parsing and Computation, defect)

Description

[Louis Pitterman]

User Agent: Mozilla/5.0 (Windows NT 6.0; rv:9.0.1) Gecko/20100101 Firefox/9.0.1
Build ID: 20111220165912

Steps to reproduce:

I have a menu wrapper with 5 menu items that are positioned inline within the div (menu). The wrapper is fixed to position right:10px and top:10px. The initial top position is -100px. After the page loads, I change the wrapper's top position to 10px in script and the css transition should do the rest.


Actual results:

This works fine in Chrome, Opera and Safari. All I need to do is change the menu wrapper's top position and the css transition fires and the wrapper eases in to place. In Firefox 9.01 on Windows Vista Ultimate, this does not work. Instead of a transition, the wrapper instantly appears at top:10px. However, if I change the wrapper's width by stating something stupid like the following,

menu.style.width = menu.offsetWidth + "px';
meny.style.top = '10px';

it works fine. If I put an alert before the statement that changes the wrapper's top position, I observe the wrapper is offscreen then slides into place after I close the alert dialogue box. I'm not sure if the pause forces a render or something.


Expected results:

Transition should fire when associated style value is changed, as per the documentation.

Comment 1

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

This bug report needs a testcase showing the bug in order to be potentially fixable.

Comment 2

[Firefox Bug Husbandry Bot]

2019-03-06

This bug is part of a group of bugs which have had an open needinfo for at least 12 weeks.

The request for information has not been answered, and we can't move forward on the bug so we are closing it.

If the defect is still present, please reopen this bug with an updated report.