First login - your user preferences/71/en

From LimeSurvey Manual

Three options are available: 'default', 'full template editor', and 'simple template editor'. Choose 'Full template editor' to get an enhanced editor (with syntax-highlighting) when editing survey templates and 'Simple template editor' to get a plain editor field. The 'default' option corresponds to the option selected in the global settings of the LimeSurvey installation.