adjust more UI on the Advanced section, and make other small code & UI tweaks

README.md

@@ -136,12 +136,18 @@ To add an icon, add to main.ts and reference with `fa` element and `icon` attrib
 ## Troubleshooting
 
 * A problem with `GET http://localhost:8080/web-push/vapid` means the py-push-server is not running
-  (and it won't work for a local app, anyway).
+  (and notifications won't work for a local app without special routing from the browser's web push service provider, anyway).
 
 * Red errors everywhere with a console message like this:
   `Error: An ID is chosen but there are no keys for it so it cannot be used to talk with the service`
   ... has happened on account switching when the current account was erased (or maybe replaced -- once I had a duplicate and I don't know how).
 
+* The error `DEXIE ENCRYPT ADDON: Could not decrypt message!` or
+  `Encryption key has changed` means that the encryption key is wrong,
+  sometimes seen after clearing storage for testing; you can make it happen by clearing localStorage.
+  Maybe only part of the storage was cleared out. Unless you got a copy of that password, you'll
+  have to erase storage and reload the identifier.
+
 
 
 ## Other