Custom Button on Suitecrm 8

I just switched from suite7 to suite8.
I have to say that everything is beautiful, but I have a problem that I just can’t solve.
I have to add some custom actions in the contact form, but while modifying the detailviewdefs, it seems that this modification is not taken. This did not happen on suite 7.

Help Please.

nothing? i have tried changing the metadata but the resul not change

hi @Linx ,
I also have facing this problem and not get any solution
i heard documentation for suite8 is not yet finished.
lead developer is working on it