Some thing odd with the close window X-button in Windows

[ScrKiddle]

RJ TextEd settings say, only one instance is allowed.
RJ Text is open, text file is open.
I press the top right close window button [X].
RJ Text window does close but stays in the taskbar and does not close to tray.

When i click the taskbar button to bring it back, all files got closed.
When i open a new instance from start-menu, RJ TextEd opens from the taskbar symbol (not tray) and for about 10ms i see the opened file and then it disappears and RJ TextEd is open but all tabs in the editor are gone and the editor shows no open file. From that point if i close RJ TextEd in the Application menu, the whole session is gone and on restart RJ Text starts with an empty session.

When i minimize the window with the top right window button [-] RJ Text goes to the tray (not taskbar).

The top right window button to close RJ Text should minimize it to the tray, and then reopen the session. But for sure it should not close to a taskbar-symbol, that is very odd behavior in the windows world.

Windows 11 64bit
RJ TextEd 16.17 64bit (by the way, it would be very handy if the version string in the about box would allow copy&paste)