It is not an issue but a wish !

[GitGilGml]

Since you rewrite your code, it would be soooo useful if you can add the following :

When you specify a WIP limit inside brackets it works very well.

When you work with combined list and specify a WIP limit inside brackets in the leftmost list it works very well.
But then, WIP limit scrapping occurs in the top title ( the merged one ).

Perhaps you're able with some special option to apply the WIP limit to a specific list, and leave the top number a simple sum of the number of cards in all sub lists.

[GitGilGml]

Sorry incomplete sentence ...
to apply the WIP limit to a specific sublist, have it rendering color due to the WIP, and leave the top number rendering a simple sum of the number of cards in all sub lists.