That’s an old issue dating from RB times. There is AFAIK a Feedback report for that. Unfortunately I’m not able to run Feedback anymore since the latest update, so I can’t check.
I couldn’t find the report for that particular bug.
I created a FR for a similar Line problem though - when adding the Line control via the keyboard, it appears in the Layout as a single pixel - <https://xojo.com/issue/32866>
Usually, when I am not able to select an object in the Window Editor, I click and drag a rectangle around the object I want to choose, but this does not works (or does not display the object as selected).