Bug 95449 – transition tweens calculate incorrectly when manipulating DOM and changing className

• Component: Layout and Rendering
• Status: UNCONFIRMED

[Onne Gorter]

Created attachment 161454 [details]
hit left/right and observe "holes"

If in the middle of an animation, and you add/remove DOM nodes, and set new endpoints, the animation tweens normally.
if in the middle of an animation, and you change node className's, and set new endpoints, the animation tweens normally.

But, if you manipulate the DOM *and* change some nodes className's, for those nodes, the positions for the new animation are off.

See the attached testcase which emulates an endless scrolling list with an animation of 1 second. Just hit left/right in quick succession and observe the "holes".

Turning off SET_FOCUS does not change classNames and the animation look continuous and without any holes.
Turning off DOM_CHANGE does not add/remove nodes, and the animation looks continues (but you cannot go far ...).

But both together cause "holes" to appear in the animation.

Even setting the same classname on an element still has the this effect, what actually gets styled seems irrelevant to this bug.

It is purely cosmetic, but it is in the way of some otherwise nice effects you can do with this.