When you display a file in the view pane, the side pane might contain buttons.
The buttons represent any actions that are defined in the File Associations
preference tool. The actions are defined in
the Default action drop-down list in the Edit
file type dialog in the File Associations
preference tool. Click on a button to execute an action. For example, if an
action defined for plain text documents is to open the file in the gedit
text editor. If this action is defined, an Open with gedit button is displayed in the side pane. To open
the file in the gedit
application, click on the Open with gedit button.
A button that represents the action does not appear in the side pane if the actions are excluded in either of the following dialogs:
Open with Other Application
Open with Other Viewer