It painfully to notice that Mendix did not release a version for Mendix 5, I have a fixed the widget to be compatible with Mx 5. (experimental), But fixed months ago! This is why I also addressed the topic at https://forum.mendix.com/questions/5984/Post-All-your-Widgets-on-GitHub
But I am not sure if i am allowed to post it on public GitHub. With permission with Mendix I will.
Though it still based on the previous version (2.1) of the tree viewer
@Ronald: Please do file a ticket! I think this should be covered by the automated conversion indeed.
@Andries: (too long for a comment) (most) Appstore widgets are not proprietary or something, but more or less a side effect of other in house development or requests. The gridview for example is the result of a widget which we initially build for the home.mendix.com admin functions only, but seemed so useful that we shared it. So feel free to publish any patches and share it further.
But, to make things easier, i'll share the original project with you, if you can build the patches in your own branch we can merge them back. That is at least the closests the teamserver gets to a git pull request ;-). If you prefer github, that is fine as well :).
Edit: since there are multiple users with your name, can you send an email to me (firstname.lastname@example.org with the email adress you want to receive the invite on?)