Remove folder prefixes only

app/src/main/java/eu/faircode/email/Core.java

@@ -791,19 +791,11 @@ class Core {
                         if (folder.subscribed == null || !folder.subscribed.equals(subscribed))
                             db.folder().setFolderSubscribed(folder.id, subscribed.get(ifolder));
 
-                        if (folder.display == null) {
+                        if (folder.display == null && display != null) {
-                            if (display != null) {
                             db.folder().setFolderDisplay(folder.id, display);
                             EntityLog.log(context, account.name + ":" + folder.name +
                                     " removed prefix display=" + display + " separator=" + separator);
                         }
-                        } else {
-                            if (account.prefix == null && folder.name.endsWith(separator + folder.display)) {
-                                db.folder().setFolderDisplay(folder.id, null);
-                                EntityLog.log(context, account.name + ":" + folder.name +
-                                        " restored prefix display=" + folder.display + " separator=" + separator);
-                            }
-                        }
 
                         // Compatibility
                         if ("Inbox_sub".equals(folder.type))