Unable to load additional columns dynamically off the edge of the screen.

I am creating a Kanban board of sorts that can have up to 15 columns, as such we want to implement horizontal scrolling. I have successfully loaded additional columns dynamically using code in this post: https://forum.webix.com/discussion/4350/dynamically-add-accordion-items

However this doesn’t work when there are too many columns to be displayed on the screen.
Here is a snippit of my code:
https://webix.com/snippet/7abad30e

You can confirm the error by using this code:
Code Snippet which gives the error when trying to minimise the column and doesn’t load the header as the title of the column either.