Upgrade to 1.0.4
I found the error is Cache TTL.
If Cache TTL = 5 (default)
New thread Widget are still sorted by ASC and will miss the recent five posts (display threads 5-10).
When I set the Cache TTL to 0, everything works fine. DESC sorts and displays the last five threads (display threads 1-5).
I don't know the Cache mode, but if Cache=0, the Widget will add 2 mysql queries, and cache=5 will add 3 queries.
The node I tested, the latest threads was a month ago, but it still missed the last 5 threads, sorting is always ASC.
A new question, I disabled the unregistered user group [View node] permission on one node, this node will not be able to display new thread Widget. I tested the Xenforo default new thread widget and it will work fine.