The main reason we don't recommend inheriting is that there are simply too many factors that one should be aware of in order to have a success. Further, we can hardly provide support if something go wrong because:
- we cannot be aware of the implications this will bring in the functionality
- we do not know whether modifications will not break something else
- we do not know their purpose and the business need they take care of
This does not mean, however, that the controls cannot be inherited or that it is a bad practice. It is just somewhat more complex and the developers should be aware of this. Actually it might be a good idea that we provide a help topic covering in more details common pitfalls.
On your other thread that began as a bug report - I have brought it to the attention of our technical leads for examination. I suggest communication on that matter continues there.
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