All effects currently active on a combatant are displayed on the Active Effects pane. This will provide a quick view of the effect description, duration, and source. This pane also allows you to sustain effect and cancel effects.
As shown below:

The colors have a special meaning:
At the bottom of this pane are two buttons:
As will all tracked object, you can undo actions in case an invalid command was executed.
All effect descriptions (except Mark effects) can be edited by double clicking on the description on the table in the Active Effects pane. Place the new text and press Enter. This is not supported for mark, in this case simply add a new mark.