Tab highlight has jagged motion

[marcoms]

The end of the tab highlight typically does not move, but waits until the end of the transition, then it jumps to its final position.

http://webmup.com/y575o/vid.webm

[marijnvdwerf]

I tried to use the javascript code as a base for a Java implementation of the indicator line. But the JS implementation appears to use a rather different animation.

The render on the specs page uses this movement:

While the javascript code from the sample would use this movement:

There are three causes for this discrepancy:

• The first one is due to the start time of the last animation. In the sample the left side of the indicator starts moving while the right side hasn't yet reached the target position, whereas the polymer components only starts moving the left side once the right side has reached the final position.
• Another cause are the easings use. I estimated that the easing function for both sides would be something like cubic-bezier(.46, .17, .23, .96). Yet the polymer sample uses different easings for both parts of the animation.
• The last reason is the duration of the animation (also visible in the charts).

[marcoms]

seems to be fixed in master, from what I've seen