I've just noticed a (new?) bug. I simply created a new Collection and then tried to create a new Collection within it. Once done (input of name and confirmation), the listing does not update (an empty Collection would still display an empty list). Furthermore, it appears the program hangs as it does not respond anymore and soon enough turns into the usual WinXP unresponsive window where you can only click on the close button. Doing so allows to terminate the program as usual.
When restarting Opus, the Collection does contain the newly created Collection.
Another potentially strange bit: the first time I tried this, I added Members to the main Collection first and then tried creating another Collection within it. After restart, the inner Collection was there, but all the Members had disappeared, as if they hadn't been saved or were wiped somehow (not sure how Collection storage works, so...)
I've been able to reproduce this consistently: go to Collections, go to existing Collection or create new one at root, then create new Collection within an existing one.
Version and OS:
Directory Opus Pro 10.5.4.0 (5080) x86
OS 5.1 (B:2600 P:2 T:1) SP 3.0 "Service Pack 3"