mCustomScrollBar with dropdown issue

I am currently working in client side, and I had the issue with mCustomScrollBar. I am using the selectpicker js for dropdown and uses data-container for that in UI and that dropdown has the search option. And I use mCustomScrollBar for that dropdown. when I search some value in that search box and if the search result size is below 5, then the scrollbar disappeared. The problem is once I enter with the dropdown of size 5, the scrollbar disappears and if I reopen that dropdown the scrollbar won't show. I debugged that issue and find that if I use the data-container, then only it causes this problem. Kindly give any better solution.