Detect Building Being Placed

[Tonex]

Is there a way to detect if a builder is placing a building? Essentially when the builder opens the build menu then selects a building, but before the building location is chosen, I want my trigger to fire. Is it possible?

 

[Da Fist]

Hum. You mean, the green square/rectangle thing is attached to the building? If yes, No. You cannot trigger that ( or so I think ), because there is no appropriate Event in GUI. Though in JASS, not so sure, I am still learning JASS.

 

[Tonex]

Yeah, I'm trying to detect if the player is in the state where there are those green/red squares.