I have a second monitor, whose center is situated at about 9:30 from my primary monitor (to the left and up slightly). Whenever I start Spark 2.5.8 in Windows, I get a second, shrunken window frame on the second monitor, with the standard four window controls on it. I can move it, drag the content section larger (there’s nothing in it, other than its off-white color), and close it. It always starts in the same position relative to the main screen - at about 10:30 (Northwest), and if I move the relative position of the second monitor (Display Properties:Settings) it will not follow the second monitor position.
It appears to serve no purpose and cause no harm. I mention it only because as a programmer, I have learned to assume that there’s no smoke without fire (forgive the pun).
Meanwhile, I’m thinking of adopting it as a pet - and calling it Flicker