Dependent OptionSet not working for 3 or more levels

Hi Everyone,

I'm following this tutorial.

https://msdn.microsoft.com/en-us/library/gg594433.aspx

However, my problem is, the solution is working well for 2 levels of dependent optionset, lets say

Main Product -> Product Type

Then it works well.

Main Product -> Product Type -> Product Sub type

Then the problem happens.

for more than 2 levels, what happens is that you can select the 3rd optionset value then it is saved. However, when you reopen it. It will clear the 3rd optionset value.

Please help ASAP.

Thanks