In Chrome, when I drag a slider both the knob and the bar disappear and then re-appear when I release.
I've gotten as far as finding that the issue arises when the "dragging" class is added to the knob and bar, but I can't figure out what about that class is causing them to disappear. I just updated to Polymer Starter Kit 1.1.1 to see if that would resolve the issue, but it still seems to happen.
It's happening only in Chrome (IE, iOS, and Android all work fine), and it's happening even when I'm using a fresh install of PSK, just adding paper-slider to elements.html and a paper-slider tag to the main content area in index.html.
I've had the same issue with Polymer Starter Kit 1.0 and 1.1.1. I'm using the current public version of Chrome (46.0.2490.86 m).
Any ideas?
I finally figured out (thanks to Peter Burns on the Polymer team) that this issue was being caused by a browser extension (MeasureIt 0.4.14). Once I disabled this extension the paper-slider works fine.