I have tried to integrate jScrollpane custom scroll bar with bootstrap select picker dropdown.
When we remove any option element from dropdown and refresh it using selectpicker refresh method/ jScrollpane scrollbar stopped working.
Please have a look on attached demo link to get more idea. Let me know the solution.
Demo URL : http://dropdown-test.iprojectlab.com/
jsFiddle URL : https://jsfiddle.net/ztqq0mzs/8/