Any Text Viewport may be designated to be an Alert Viewport which will ``pop" to
the front of the screen whenever it is written to. Several Subprograms exist
whereby a Viewport may be designated as an Alert Viewport (or such a
designation may be cancelled) and an Alerted Viewport (i.e. one which has been
``popped" to the front of the screen) may be restored to its prior visibility
and priority. Wildcarding is also supported, whereby all Alerted Viewports
may be restored to their normal visibility etc.
One restriction on Alert Viewports is that only calls to UI_DISPLAY_LINE or
UI_OUTPUT_TEXT will cause the target Viewport to be alerted. Calls to
UI_DISPLAY_CHARS will not be detected.