Thebutton allows you to filter out comments displayed on the screen. This can be helpful when multiple users have submitted comments and you only want to see comments made by a certain user, or by a certain thread name for instance. To filter the comments, click the button. A dialog appears, in which you can type in a regular expression you wish to use as a filter.
Once you apply your filter, you will see the results in the main screen. Note that the background will turn blue, indicating that a filter is active. Thebutton font will also be blue as an indicator that a filter is active. To remove your filter, simply click the again and remove the regular expression you entered, then click apply. The filter will then be removed.