What determines the divider lines in left-hand list of lists?

Support
#1

In the lef-hand display of the names of all the lists, there are divider lines between some lists. What is the logic determining which lists are separated by such divider lines and which are not? And second, is it something over which the user has any control?

Thanks

#2

Hi Lucas,

Currently when you make a new list, a divider is made above the new list.

You may drag and drop lists to remove/adjust dividers. If two of them meet, only one survives.

Thanks!