A little background first, the default (native) OSX VNC program sucks when trying to use it with UNetLab.
Chicken of the VNC, on the other hand, works great. But there is nowhere in Chicken to set it as the default app.
There is a little program that will come to the rescue, and this is RCDefaultApp. It is a little download, and installs an app (Default Apps) in the System Preferences.
From there you have a much more granular control over what gets launched. For example, I can now set Chicken to be the default app for VNC connections:
Now when I click on a VNC node in UNL, it launches Chicken instead. I still need to click "Connect", but it launches Chicken:
Much easier!
This does not allow the addition of custom handlers though. So this means that we cant add one for Wireshark. But I have that solved, and once it's tidied up a bit, I'll do a post for it.