The caption isn’t sliding but fading in and out


The slide effect is disabled for technical reasons on Internet Explorer 8 and lower. It gets substituted by the simple fade animation. If you still prefer sliding, try the Captions tab > Caption style setting's Mixed option. It'll slide only the bottom part of the caption, while the top half will remain visible.

This troubleshooting fix was posted in Visual glitches on June 24, 2015