You can set the amount of characters per subject that can be typed before a warning indicator will be displayed (the background will turn amber).
Right-click a subject, a menu will appear, click 'Set warning number of characters'.
In the text box, type in the approximate number of characters before the warning indicator will appear.
Note: Enter zero ( '0' ) to turn off the warning indicator for this subject.
If this is the first time you have set-up a warning amount you will be asked if you wish to turn on the character limit system. Click 'Yes'.
For more information about character limits, see the text length limits section.