Checked out the branch and it does fix the issue.
(One needs to re-execute the cells once first or clean the local storage, because whatever was in the local storage before your fix was probably wrong. )

@jdfreder thanks for the fix, @SylvainCorlay thanks for the report and confirmation of the fix.

@jdfreder is this something that can be reasonably tested?

phantomjs apparently supports local storage.

@minrk it's ugly, but the last commit adds a test.

It wasn't possible to test the return value of get_state directly? That wasn't incorrect?

In general, now that you are using the local storage for the widgets, Phantomjs' local storage should probably be cleared before running any test suite.
http://stackoverflow.com/questions/18408868/disabling-localstorage-on-phantomjs-for-clean-testing

for what it's worth, @jdfreder's analysis and fix of the problem seems appropriate to me.

Yeah, 👍 on this.

@minrk yeah, the get_state call is what was returning an incorrect value. I implemented the test the way I did so it tests the entire feature.

Makes sense, you just said it was ugly, and I thought there might be a way for it to be less so. Thanks!