hello newcopatriot,
I visited the website you referenced and I don’t see any code in the source that is related to this plugin, Simple Side Tab. If it is de-activated or uninstalled, the code won’t be written to the page so it will not affect anything else you have active. If it is active, it uses it’s own prefixed CSS classes so it should not interfere with anything else on your website.
If something else is going on that I am overlooking, please send further details and maybe a screenshot or two.
I do see a share bar that appears when you scroll down the page, is that what you are referring to?
newcopatriot,
If you still need help, please let me know.
Scot