Typing in the "Content List name" dialog box produces double characters
When typing in the "Content List name" dialog box, every character typed appears twice. For instance, typing
Tested with macOS 10.11 and OpenMW 0.41.0.
(RM-3911 from redmine: created on 2017-06-07 by Will Herrmann, , closed on 2018-06-15 by Will Herrmann, relates #2862 (closed))