Put the slideshow code in a center-aligned division:
<div style=”text-align:center;”>SLIDESHOW</div>
Using an old version of a plug-in is poor practice. If the developer isn’t interested in resolving the issue — 8 months should be enough time — the solution is to switch to another customizable contact form.
This issue is NOT Resolved.
I took the same steps as d1git above and obtained the same results. I’m pretty sure this only became a problem with the upgrade to WP 4.8.
The problem is in CF7.
Wordpress Version 4.7.3
I was running PHP 5.3. Changed to 5.4, which resolved this issue.
Thanks for your prompt attention!