The Add Code feature, in the editor toolbar, allows you to insert and separate code from the rest of your message. The inserted code, which is placed inside a box and uses a mono-spaced font, maintains the indent style you use to convey structure.
Clicking on the Add Code button opens the code editor window. The available modes control the context awareness of the editor and, depending on the selection, will display syntax highlighting as well as error/warning messages. Selecting the Text mode disables the highlighting.
Click on the OK button to close the editor and insert the code into your message. It is important to note that the code will not display the syntax highlighting after it has been inserted into your message.