I download the open panels plugin code: [code is removed]
I need to know how to make the panel scrollable.
It is opening as a full page and don't show all the text.
You do not need to do anything to make scrollable for panels. When your panels have long contents the scrollbar will show automatically.
I checked your site and see some errors. Maybe it causes the plugin is working wrong. Please re-check your site and fix the errors.
I also see your site is added many jquery library versions. It is not a good practice. You should consider to use only one jquery version for best performance and stability.
P.S: please do not show your purchase code on a public place. Just use "Add license" feature on this site to add your purchase code. I will remove the purchase code in this ticket (I saved your code for your account).