Tree nodes default to collapsed state, making navigation easier

[ojsrb]

Changed the tree.tsx component to make the drop downs default to collapsed, making it easier to find the variable you are looking for without scrolling very far.

[illinar]

I support having an option to collapse the tree by default, but this has to be configurable at the component level.
I suggest adding a property to control the behavior:

/** Indicates that nodes are collapsed by default. */
collapsedByDefault?: boolean;

That said, I don't think it is sufficient, since searching for the node doesn't automatically expand matching branches, resulting in somewhat awkward UX. I don't currently see a universally acceptable approach though, each solution requires some sort of compromise.