When you are debugging using DBMS Output and polling say every 3 seconds, every polling refresh will lose any selection you have made or caret position - even if no new outputs were found. This is BEYOND irritating, especially if you are viewing a certain part of the output or selecting parts of the output to paste into a document or an email. The output should maintain any selection and caret position, even if the output has added new data, but the least it should do is not affect selection or caret if nothing is added. It’s not hard to do with editors.
Why have you waited so long to report this!?
Good idea. For next beta if you have moved the caret to a position less than end of document or if you have a selection the memo is not scrolled and any selection is retained. If the caret remains at the end of output without selection then output scrolling is performed as it does currently.