Problem with OpenFcn parameter in Simulink

I am creating a Simulink block library and it contains several empty subsystems. I want these subsystems to open up other .mdl files when the user double clicks on them, I have used the OpenFcn parameter to achieve this and it works fine. The problem is when I configure he OpenFcn parameter Simulink no longer displays the subsystem in the library browser. If OpenFcn is left empty the subsystem is dispayed but once it is assigned the block vanishes from the library browser. What is happening here?

[Kaustubha Govind]

Could you try creating a mask on the subsystem and add a parameter named 'ShowInLibBrowser' to the mask? I think this should make the subsystem show up in the browser.

[Charles]

Yeah I did that and it works but I don't understand why this is neccessary. I guess it works so maybe I shouldn't complain.