The description of what you’re after is still pretty vague. However, you can solve any problem by breaking down what you want to do into smaller doable steps.
It looks like maybe you want to drag icons from the left onto the top. Maybe you could give the icons the drag and drop behavior. Then when you drop them (the one drop trigger) you’d check if it’s overlapping the top bar, and if it is then do something to position it in a nice way. And it’s not overlapping the top bar on drop just move it back to the left toolbar. You could also just move it back to the left toolbar on drop but create a duplicate on the top bar.
To position them in a nice way on the top bar you could pick all the icons overlapping the top bar, then “for each” the icons, and set the icons position to something like (topbar.x+icon.width*loopindex, topbar.y). That would put them in a nice evenly spaced horizontal line.
Just some rough ideas that could be a possible starting point.