[QUOTE=Shindoh]If I check for 'Is Overlapping', then I expect it to be a continuous check and not a one time result. And perform actions according to "as long as overlapping". If I wanted them to be executed once I'd use the 'perform once' expression.
But this way it would be useless in a while loop, unless I used the System Condition.
In other words, if I applied actions to the Sprite Condition, it would make no difference if they are in a while loop or not, this way. It would behave the same.[/QUOTE]
I know what you mean, although we don't have exactly the same point of view. I wouldn't expect sprite's "is overlapping" to bahave as it does, but I wouldn't expect the system's one to behave as it does, either!
And here's why. CC is a tick-based system. Every tick is like a short period of stopping the process. You can do whatever you like within that tick, and everything gets computed, and the whole process will continue as soon as you are done. So one tick may use 10ms to get computed, another one may need 2 seconds. But I'd expect consistency, everything that's true at the beginning of a tick should be true throughout the tick. Of course that would render loops within a tick almost pointless, but one could rely on the status of a tick.
I suspect that "Blue Sprite overlaps Red Sprite" is only checking before entering the tick and then gets confused by continously asking for the state of that Blue Sprite while at the same time altering its position value. I come to this conclusion, because I can make it work, if I avoid using the overlap condition as a while-condition.
+ System: Always (every tick)
-> Sprite: Set position to MouseX, MouseY
-> System: Set global variable 'done' to 0
+ Sprite: Sprite overlaps Sprite2
-> System: Set global variable 'done' to 1
+ System: While
+ System: Is global variable 'done' Equal to 1
-> Sprite: Set X to.X - 1
++ Sprite: [negated] Sprite overlaps Sprite2
--> System: Set global variable 'done' to 0
Believe it or not, this one works. The only difference is that the while-condition is a test against a value of a global now, and that global will be altered in a sub-event that checks for overlapping, again. Confuses me.