The Message Filter Dialog allows you to select which message types will be shown in the Event View panel, and which will not. To call the dialog, press the Customize button in the Filter panel (it is displayed when Filter Panel is enabled in the Event View context menu or on the Event View toolbar).
The dialog shows the list of message types on the left, and to the right a check box for each. Only checked types will be shown. Use the Select All or Unselect All buttons to check or uncheck the entire list.
When all types are checked or unchecked, Event View's Filter panel displays All Messages or No Messages correspondingly. When not all are checked, the Filter panel lists them. To disable the settings of the Message Filter dialog temporarily, simply disable the checkbox in the Filter panel.