Problem resizing the download window

You know hot when you download a file a new window opens allowing you to navigate to the folder you want to download to? I usually keep that window rather small. but last night in the middle of navigating the window suddenly expanded so that it nearly filled the screen (except for maybe a quarter of an inch on all 4 sides). I went ahead with the download and the widow vanished as usual when the download started. However, the next time I downloaded the window was just a large and I could not drag in the sides to make it smaller. There is also a little triangle of dots in the lower right hand corner of the window which you grab to shrink the window keeping the same relative proportions of the sides. When I tired to click on that the pointer still couldn't push it in to make the window smaller and the dots vanished. The problem has persisted after the computer was shut down overnight and also after a restart this morning.

I am running the latest version of Windows 10 on a PC desktop. The problem occurs only in Chrome; in Vivaldi the download window is normal and can resized as usual.

As a diagnostic have you checked Internet Explorer for the same issue? Start, W section, Windows Accessories. If it seems normal there as it does in Vivaldi then the issue is with Chrome.

Thanks for considering my problem.

I haven't opened explorer in years, but I did just now and its fine, so you're right it must be a Chrome problem.

You don't, by any chance, use Actual Window Manager? I had a similar problem with Opera (also a chromium based browser) where any window opened within Opera showed very large. After a lot of fretting I opened the AWS specific settings, where I set Opera to open to a given size. And realized that all windows within Opera were the same ID as Opera's main window, so they all follow the same rule. I killed that requirement and now adjust the main Opera window by hand.

No I don't . I didn't change any settings or anything like that. It just suddenly happened. I was somewhat distracted at the time (children in the room) and I may have pressed the wrong button in the download window itself, but I ca't see any relevant controls there.