There was mention of this issue by someone else a short while ago, but they never found a solution or did and never posted the outcome.
First off, the form displays exactly the way I wanted it to within the tab. For configuration, I set tab slide to "widgeted" area, used gf form widget within it. However, when you click submit on the form, it takes the visitor to a blank page that is only displaying the form itself, and doesn't even submit the form.
When I used the inspector to examine what the issue was, the action is calling to "wp-content/plugins/tab-slide/templates/Widget.php" which I'm assuming is causing the error.
The tab is displayed on every page, here's a LINK.
Thanks in advance!