Fatal JavaScript error when grid editing "Time" column

[ibennetch]

Steps to reproduce

1. Create a table with a primary key and 'time' column, also checking the NULL checkbox for the time column, although this probably isn't critical.
2. Insert some data.
3. Browse the data, then click to edit the time column.

Expected behaviour

Editing should occur without an error

Actual behaviour

The pink banner is shown "A fatal JavaScript error has occurred. Would you like to send an error report?". Clicking the "Show report details" button doesn't do anything.

Server configuration

Operating system:
Debian
Web server:
Apache
Database:
MySQL
PHP version:

phpMyAdmin version:
git master

Client configuration

Browser:
Firefox
Operating system: