Having knowledge how the MESSAGE function is implemented I don’t understand how your message is displaying on your system (as well as situation from the topic). My only guess is that drawing of static text controls has been changed sufficiently in Win11, or you do use some hook function for MESSAGE.
Please use the WinSpyEx utility to provide more data:
- position and size information from the General tab
- font information from the Details tab
- it would be useful to have screenshot of the message box when the Finder Tool is over the text.
Then, switch to the Windows tab and click the link for the Parent window at the bottom. The size information from the General tab is required.
This is how your message is displaying on my computer (Win8.1):
