Why does the main window of an X11 application sometimes not appear in OS X

I have created Perl/Tk application for OS开发者_JAVA技巧 X compiled using ActiveState PDK PerlApp 8.2.1. The application requires X11 to work properly on OS X, and everything works fine on my own computer (OS X 10.4.11) and others report it working well on OS X 10.5 and 10.6.

But, I have also received several reports from users, for example on 10.4.11 and 10.6.7, that after starting the application, the program seems to run but no main window appears.I have created Perl/Tk application for OS X compiled using ActiveState PDK PerlApp 8.2.1. The application requires X11 to work properly on OS X, and everything works fine on my own computer (OS X 10.4.11) and others report it working well on OS X 10.5 and 10.6.

But, I have also received several reports from users, for example on 10.4.11 and 10.6.7, that after starting the application, the program seems to run but no main window appears.

(Just to clarify the meaning of "seems to run", users can launch X11 (so it's installed!). Also, after launching my application, a new X11 menu bar appears and they can click "About..." and can see the "About..." window for my application.)

I cannot replicate the bug here and the users say that no errors appear on the Terminal command line when they launch the application.

Has anybody experienced a similar problem and know a way to fix it? It seems to be an issue with X11, but I am happy to change my own code to avoid this issue.

I guess the first thing to check is that they are launching from the X11 terminal, rather than the normal one. (and that they have X11 installed).

PerlTK might be hiding the errors in that case?