Modify MASTER switch for device-alias database

In my fabric there is one MDS9513, and some 9124e (modules in Blade Enclosure).

I don't know the reason, but DCNM is using one of those 9124e as "master" for device-alias database.

I want to use the 9513 as master... how do I change the master switch for that?

I tried to tick the box "master" in the row that corresponds to MDS9513 and then commit changes, but this didn't change the master switch.