Entering "Sound Name" in "Sound Properties" will freeze Synfire. (OSX / Device Descriptions) 

I also have a problem using the dropdown list...

When I chose i.e. "Piano" in the dropdown list from device description

it takes a couple of seconds (~10 plus) to appear in the list.

Can't explain it, I'll upload a .gif for clarification.

How many device descriptions do you have?

None. I'm making new ones. (I can't say if there are any other/older ones that SF2 probably doesn't recognize?)  

Something seems to be slowing down updates of dependent objects.

Yeah, I thought so, too. I am guessing this has to do with the SF2->engine communication, but I am shooting in the dark right now.

Device Description Menu --> On name-entering:

There's also a hefty lag until I can do other stuff again.

(Btw: I don't know why "LiceCap" (ScreenRecorder) doesn't show the clicks anymore...)

If possible, you should do that only with global devices and only when you create them. 

Thank you for the tip, but I did that already. Unfortunately, I didn't include the "Global Device Description" in the screen-recording.

But here is a different instrument, but in "Global". 

In the first half, I click some buttons after I "renamed" the instrument. Then nothing happens. After that, in a few seconds,

the GUI registered the clicks. (even if I am somewhere else with the mouse cursor... )

Crazy, huh? :)