Static Preview Settings forgets custom hostname when Brackets reloads

I changed the hostname in the Static Preview Settings pane from localhost to mycomputername.local.

It works fine; I can access the server from other devices on my network.

The problem is this: when I restart Brackets, the Static Preview hostname is once again localhost, as if I had never changed it.

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Update: I disabled all other extensions, no difference.
(extra info: my operating system is Mac OS X Yosemite)

After experimenting, I was able to get the hostname to stick by changing the value of sbruchmann.staticpreview.hostname manually in Debug > Open Preferences File.

It appears that the extension is not updating this value when it is changed using the Static Preview Settings pane.
Update: The port is not being set either.