I have a queue on a test instance which has 4 messages in the DLQ. However, I can't delete them when I open the "View dead letters". I haven't experienced this issue on production yet. But since I use Atom queues a lot, I would like to know what's going on here. And how I can reset the counter. See screenshots below.
Btw: I'm aware of the fact that Boomi purges messages: see quote below which has been copied from the Atom message queuing help file.
NOTE: Documents referenced in currently enqueued messages persist until a scheduled purge occurs. This is true even while the Atom or process is configured to enable purging of data immediately following process execution.