[ JDK VERSION : 1.8.0_45 ]

Steps to reproduce:

install netbeans with glassfish.

use netbeans (or command prompts) to create multiple domains that all share the
same set of ports.  This is done one domain at a time, with all domains stopped
(making the default ports available for re-use).  If you want to make it really
interesting, use a different password for each domain's admin user.

register each of the distinct domains with NetBeans

start one of the glassfish domains.

at some point, you will see multiple dialogs appear asking to supply / confirm
the credentials.

it appears that netbeans is periodically checking for matches between the
available ports and registered servers, and, when there are multiple servers
using the same ports, causes all such matching registrations to check,
resulting in the dialog appearing.

however, it correctly shows only one of the instances is running (evidenced by
the badge showing that the instance is running, while the others are not).

one question you may have is: why are there multiple domains with the same
details?

the answer is: when I work on multiple projects, each having their own domain,
I want to have my development environment match the ports that are in use on
the production / qa / integration etc environments, so, I end up with multiple
domains that have exactly the same ports being used.  of course, only one of
those domains is active at a time.

netbeans has project groups, which is great, but, it does not include in that
grouping, the details of server registrations!  it would be nice if that could
happen, but it doesn't.

a solution to the repeated multiple prompts would be much appreciated.