Why my model not regenerate code?

I mask an empty subsystem be a block, and set some parameters. When in tlc code generation stage, I use a m-script to get the parameters of the block, so I can control the different code generation. But when I modify the parameters of the masked block, the model skip the code regeneration and go ahead. WHY? I searched in MathWorks.com, and found a bug report link ( http://www.mathworks.cn/support/bugreports/806992 ) can force the code to regenerate. But I do not think my situation meet this, and not a good solution. By the way, I use Matlab 2012a, and in 2012b my problem also exist. Is there a better way to fix my problem?

[Kaustubha Govind]

I think the problem is that you have an empty subsystem, so Simulink Coder thinks that it can skip it.

[Alon Jun]

Thank your reply. Yes, I also think maybe this reason. But in Embedded Coder library, it has a block Target Preferences. This block also mask on an empty subsystem, why it works right? I think Simulink Coder may have a mechanism can avoid my problem. Can you help me, thank you!