Steps to reproduce:

1. Visit https://en.wikipedia.org/wiki/Deliciosamente_amoral?veaction=edit

2. Attempt to manipulate the contents of the infobox by clicking the puzzle piece icon associated with it.

Expected behavior:

Infobox parameters should be editable.

Actual behavior:

Template editor invocation fails with the following error on the console:

Uncaught TypeError: Cannot read property 'description' of undefined

Chrome/Ubuntu

Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=49493