Closing image preview after opening image changes focus to different instance

[Callistemon]

A second error discovered tonight, is that if two instances of Duplicate Cleaner 5 are running, opening an image preview in one, right-clicking an image to open, and then closing the image preview switches the background window to the other instance. This does not occur when the image preview is closed without opening the image first through the context menu.

[Callistemon]

An error occurred when attempting to diagnose how exactly the error was occurring.

It does not require two instances of Duplicate Cleaner. If there is only one instance, the one window just minimizes to any other application that is behind it, or the desktop. It was just that the other instance of Duplicate Cleaner happened to be directly behind the one that minimized.

[Callistemon]

It actually does not minimize the instance with the image preview being closed. It only brings forward whatever window is behind it, which may be Duplicate Cleaner or something else. If the window behind is not maximized, the background window will appear above Duplicate Cleaner, and minimizing the other window reveals the Duplicate Cleaner window was not minimized.

[DigitalVolcano]

It sometimes does something similar to this when debugging, but I can't replicate the steps with the full program yet. There must be a certain combination of events..