Sorry can't open the file due to plugin dependancy.
Use overlapping test (overlap at offset) to check wether there is a bar below it. When there is no bar, move it down respectively.
Moving a bar to next column is done by picking next bar after the current one. For example current column has UID 15 and right next to it has UID 16. So we just need to reference current active column UID (15) to the next (16) by add 1 (15+1) on instance variable. The rest would be reposition the bar itself to that column reference.
Thanks for the reply. I'll remove the plugin and I will upload it again. I think it is better if you see the example to figure out my problem. Please, wait a few minutes. I will let you know when I have post the new capx, ok? Thanks in advance.