run the following script:
eh1 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [1,0,0,1], player modelToWorld [-1,3,1.5], 0, 0, 0, "<1>", 1, 0.05, "PuristaMedium"]}];
eh2 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [0,1,0,1], player modelToWorld [0,3,1.5], 0, 0, 0, "<2>", 1, 0.05, "PuristaMedium"]}];
eh3 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [0,0,1,1], player modelToWorld [1,3,1.5], 0, 0, 0, "<3>", 1, 0.05, "PuristaMedium"]}];
you will see 3 icons <1> <2> <3>
now run:
removeMissionEventHandler ["Draw3D", eh3];
removeMissionEventHandler ["Draw3D", eh2];
removeMissionEventHandler ["Draw3D", eh1];
all icons removed successfully. Now do it again:
eh1 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [1,0,0,1], player modelToWorld [-1,3,1.5], 0, 0, 0, "<1>", 1, 0.05, "PuristaMedium"]}];
eh2 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [0,1,0,1], player modelToWorld [0,3,1.5], 0, 0, 0, "<2>", 1, 0.05, "PuristaMedium"]}];
eh3 = addMissionEventHandler ["Draw3D", {drawIcon3D ["", [0,0,1,1], player modelToWorld [1,3,1.5], 0, 0, 0, "<3>", 1, 0.05, "PuristaMedium"]}];
3 icons <1> <2> <3>. Now remove event handlers in the order they where added
removeMissionEventHandler ["Draw3D", eh1];
removeMissionEventHandler ["Draw3D", eh2];
removeMissionEventHandler ["Draw3D", eh3];
result <2> and error message in rpt. The event handler is not removed.
Pretty severe issue.