Preferences > Behavior page > How to (behavior) >
How to: not include notes in the system list of opened windows
Right click on program icon appears in system notification area and choose "Preferences" menu item from pop-up menu or click on button on PNotes Control Panel.
When "Preferences" dialog appears, choose "Behavior" page.
In order to remove notes from internal windows list of operating system (shown when Alt+Tab is pressed) check the appropriate check box:
Default value: unchecked.
Note: changing this option requires all visible notes to be reloaded.