Ok. Ok. Ok. I confess to terminal stupidity
I swear I've looked under the E-mail Reconciliation several times to see if there was something to be changed there, and have never seen anything. Now suddenly, if I click the trackwheel, a list of options pops up! one of them is "Delete on:___" It was set to "Prompt". I changed it back to "handheld" and it works just like it used to!
I did look under Reconciliation for any additional accounts by pressing the spacebar, but nothing showed up. I don't use the Blackberry.net e-mail account, only a pop3 account by my internet provider for work and home. But even that one didn't show up under any kind of list.
Neither here nor there in the grand scheme of things... my one-key delete works again!
Now who would like to posit an answer as to how that changed in the first place???