When you edit the Provisioning Requisitions you can click on the Icon for
"Clone the set detectors and policies of the xxx Requisition"
After this you get an input window titled "Clone Foreign Source Definition" and "Source Foreign Source" which leads you to think you have to select the source to clone from.
After selecting a "Source" and hitting Enter you will be informed you overwrote the "Source" as in reality this is the destination requisition you will overwrite.
When you look at the "Source" that was overwritten it is not marked in red, so you don't see immediately that you changed something there. Even after a restart of OpenNMS it won't be resynch'd and the foreign-source xml file will still be unchanged, so it's difficult to see what happened.
It's quite tricky to get back the overwritten definitions - you have to copy the correct xml to the pending directory and resync.
I propose to change the text in the occuring window from "Source Foreign Source" to something like
"Clone Foreign Source Definitions [show name of actual selected source here] to following Foreign Source"
and, after selecting OK, show additional warning like "Warning, you will overwrite Foreing Source xxxx with the Definitions from Foreign Source yyy. Are you sure? Cancel | Yes