There are currently two options to open a file when other image window
already exists: to open it via main GIMP window or to do it via image
window. They are rather equal from the user's POV and the choice
(unconscious) depends on the currently active window (at least for me).
But the result differs: in case of main window menu the file cursor
remains at the position of the last opened file. It is very convenient.
In case of image window the cursor is "lost" and no file is selected.
Even more, trying to open a file via main menu would have the same
result - the cursor is already lost.
I think it is a bug and would suggest the next behavior in case of
opening a file via image menu:
1. the file cursor is set to the last file opened in the session as
currently is done via the menu from GIMP main window.
2. the file cursor is set to the current file from the window with the
image (even if it is opened from a directory other than the last one) if
it isn't a new file. The result of the second option would become equal
to the first one if only one image is opened simultaneously.
The file selection behavior could be based on personal preferences (in
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