Cmd-W ignored while running in Xojo 2021r2.1

Old project started while Real Studio was young does not recognize the Cmd-W order (so, do not close the window.

Not everywhere, only with the same window (with an HTMLViewer, a TextField and two buttons; test to load the text & html of a web page).

Nota: that window have a MenuBar (MainMenuBar), but its name (title) is Unknow.
In old Xojo, that command works.

Yes, I know, current Xojo versions are for New Project(s).

PS: No, my topic is not similar to Web App…:japanese_ogre:

FWIW