Steps to reproduce:
1. Start the creation of a new event
2. Try to edit the title
You have to click on the pencil icon.
Clicking in the empty field should enable its edition.
This problem has been solved by pull request https://bitbucket.org/opencast-community/matterhorn/pull-requests/1338/t-mh-11849-improve-keyboard-accessibility/diff which has been merged to develop. I therefore close this issue assuming nobody would want to backport it to 2.3.x.