Drag and drop doesn't honour the solid behaviour..
From the link:
[quote:2whyygz6]It affects the following behaviors:
8 Direction, which is blocked by Solids
Bullet, which can optionally bounce off Solids
Car, which bounces off Solids
Line-of-sight, which by default has line-of-sight obstructed by Solids
Platform, which can land on Solids. Platform cannot jump on to solids from underneath - for this, use the Jump-thru behavior.
Pathfinding, which by default uses solids as path obstacles.