When creating a slider in Toolset Blocks the Lightbox shows a large amount of closing buttons. The issue seems to be that every time an XMLHttpRequest is done the lightbox appends a new ".lb-dataContainer" element without deleting the old one. After some debugging the specific code responsible seems to be in "toolset-blocks/vendor/toolset/blocks/public/js/frontend.js". See screenshot.
To reproduce the problem:
1. Create an WordPress environment
2. Install Toolset Blocks
3. Create a page with a Toolset Blocks Slider
4. View page
5. Make a XMLHttpRequest (or multiple) the endpoint doesn't matter. (see screenshot for the code I used while debugging)
6. Open Lightbox
This is a known issue and was previously reported by one of our team members. Unfortunately there isn't a solution at this time but i've added your ticket to the issue tracker as well so that I can get updates on the issue from our development team.