overflow-y css hack seems to work

"!important" makes me [nervous](http://css-tricks.com/when-using-important-is-the-right-choice/), except in the context of inline style supplied by UI widgets we don't (want) to control, or utility classes. This doesn't seem like a utility class. 
Does jsTree actually add inline styles to set overflow-y on a containing div?
Is there a higher-specificity selector you can latch overflow-y onto so that you can go without "!important"?