Steps to Reproduce

Run sample in 8.6.1 FL:
http://zkfiddle.org/sample/fa4hde/1-zk-slider-sizing

<zk>
   container
  <div height="600px" width="600px" style="border: black 1px solid;">
  	<slider/>
  	<div height="250px" style="border: 1px red solid;">other content</div>
  	<slider id="sli" mold="knob" />
  </div>
  <button label="set 50" onClick="sli.setCurpos(50);"/>
</zk>

Current Result

The default height of the slider in knob mold is equal to the inner height of the parent container.

Expected Result

Slider in knob mold should be 200px by 200px if no size is specified

Debug Info

the height comes from client side:
setHeight (zk.wpd:formatted:42588)
_syncSvgHeight (zk.wpd:formatted:42575)
_updateDom (zk.wpd:formatted:42662)
onSize (zk.wpd:formatted:42753)

Root Cause

Workaround