Limiting adding just one instance of a status marker to a counter?

Is it possible to prevent adding multiple similar status markers to a Unit counter? For instance through a Key Shortcut a “Suppression” marker is added to a squad. But pressing the same Key shortcut adds another… is this preventable?

Sure, you just need to have the key shortcut activate a Trigger Action with a condition that checks if the status marker is already there, and only passes the command on if not. (To be more accurate, the condition would check that the status marker isn’t there; it will only trigger if the condition is true.)

Experimented a bit (as I am not that versed in all the ins and outs of Vassal, many times I do a trial-and-error approach until I succeed :)) and it can be done with a Dynamic Property, that reacts to the keyboard shortcut, which initiates the addition of the marker to the counter. This flips the DP to “1” for further checks.The Trigger Action checks it during any subsequent marker addition and sees it already at “1”, thus does not initiate the second key shortcut, which actually puts the marker out.