Hi!
With the parent / children change, the default limit was set to 300, but is not fixed and is possible to remove it.
Why? more than 300 children nodes is huge and unusable tree. We could consider paginating it, but in a long perspective will be better if you can reduce the children adding groupers as periods, mints, or other concepts, It's very rare that a tree with more than 300 nodes would be needed.
So, you can remove it, changing the value in file:
Line 68
// limit
$default_limit = 300;
And change it as you need... But, as I mentioned, try to reduce the children in the tree.
Best
