Hi,
A new ACTIVE RECTANGLE object named SURFACE Flag is available since version 1.1-31 and is the perfect object to FLASH YOUR SCREEN or any area when an even occur like when OSP (Optimal Shift Points) is triggered.
The SURFACE FLAG object is triggered by default by a Marshall or External led state in addition to EVAL Math expression on telemetry data and SLIMax Mgr Pro OSP function is set by default to Marshal LED 1 and 6. So it's very easy to flash the screen
Create a new SURFACE FLAG object,
resizes it to the entire screen
the object is RED by default, change its background color and its transparency if needed
now if you edit its properties you will see the object is triggered by default when MARSHAL LED 1 is ON, so you are done! The screen will flash when OSP is up.
That's it!
EDIT: advanced user can use the EVAL Field to set the SURFACE FLAG based on telemetry

