My scroll bar on userform can't be scrolled
<p><a href="https://i.stack.imgur.com/P1ahg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/P1ahg.png" alt="enter image description here"></a>
I have a userform that was created with a scrollbar. This scrollbar can scroll only when I use mouse courser to drag it. However, I find that it cannot be scrolled with the mouse scroll (scroll wheel). </p>

<p><strong>How do I solve it ?</strong> </p>