v4.0.0 Bug report: Glitch with slide control lines

Hello @themefic,

we just updated to v4.0.0 of your great plugin. Unfortunately we found a glitch in it.

On the frontend you have the control element/button in the images to perform the slide left/right. It should consist of a center circle with two left/right arrows and above and beyond the center circle a line to the top and bottom of the images.

With v4.0.0 the line to the top is missing, but there is a vertical line in the circle itself.

We proved this in several browsers. This problem hasn’t been there with v3.5.1 before, so it must be a bug in the new version.

Looking forward to a fix, thanks for your great work!
-doffine