Ugly scroll bar in package


I am not sure what I am doing wrong. I get scroll bars like this just for my package view. Notice that the editor view scroll bar is okay:

Unless I add the following:

     ::-webkit-scrollbar {
        width: 8px;
        height: 8px;
     ::-webkit-scrollbar-corner {
         background: @scrollbar-background-color;
    ::-webkit-scrollbar-thumb {
        background: @scrollbar-color;
        border-radius: 5px;
        box-shadow: 0 0 1px black inset;

And then its okay:

Do I need to add this less or is there already a class I should be using?