[ASK] Show Object with Drag and Drop Condition

I'm sorry, i haven't told you that i've already tried to do it with hitTestObject function, but it doesn't work, the D button never shows up even i dragged the squares on the right spot, here is some of the actionscript :

Square_4 = pnotq

Square_5 = notq

Square_1 = notp

/* Stop at This Frame
The Flash timeline will stop/pause at the frame where you insert this code.
Can also be used to stop/pause the timeline of movieclips.
*/
stop();
//Hide and Show Actionscript
if(Square_4.hitTestObject(Target_2) && Square_5.hitTestObject(Target_1) && Square_1.hitTestObject(Target_3)){
Next.visible=true;
} else {
Next.visible=false;
}
//ButtonMode Actionscript
Square_1.buttonMode = true;
Square_4.buttonMode = true;
Square_5.buttonMode = true;
//Some part of the Drag and Drop Actionscript 
(I made drag and drop for all the squares (1-7))
var startX:Number;
var startY:Number;
Square_4.addEventListener(MouseEvent.MOUSE_DOWN, pickMe);
Square_4.addEventListener(MouseEvent.MOUSE_UP, dropMe);
function pickMe(event:MouseEvent):void {
    event.target.startDrag(true);
    startX = event.target.x;
    startY = event.target.y;
}
function dropMe(event:MouseEvent):void {
    event.target.stopDrag();
    var myTargetName:String = "target" + event.target.name;
    var myTarget:DisplayObject = getChildByName(myTargetName);
    if (event.target.dropTarget != null && event.target.dropTarget.parent == Target_2){
        event.target.removeEventListener(MouseEvent.MOUSE_DOWN, pickMe);
        event.target.removeEventListener(MouseEvent.MOUSE_UP, dropMe);
        event.target.buttonMode = false;
        event.target.x = Target_2.x;
        event.target.y = Target_2.y;
    } else {
        event.target.x = startX;
        event.target.y = startY;
    }
}