I don’t know if this is so much of a bug report so much as it is a fix for people searching for the same information. Classic Slider is an older design element, so I don’t expect to see any development happen to it. There are without a doubt better ways to insert a slideshow into your webpage, but Classic Slider is easy and it’s there. So I’ll use it till I can’t.
Issue: I’m updating my website to use v2 elements and suddenly my Classic Slider slideshows don’t appear. It’s not a visual glitch (which sometimes can happen). They do not appear on the front end of my site either.
Quick Fix: Classic Slider does not like the flexbox option of columns. If you are using the flexbox to align center objects with no specific width, try turning flexbox off. The issue arises with the Classic Slider needing to reference a set width of it’s container. Flexbox does not use set widths, rather calculated widths based on used space.
Permanent Fix: As stated, I don’t expect Classic Slider to be updated. So the permanent solution would be NOT to use the Classic Slider. Consider Revolution Slider, a “pro” plugin that comes available with X Theme.
Hope that helps.

