For consistency with Plank where app icons get grabbed in the center, but also grabbing a .desktop file in the top left corner like it is now make it go partially out of the screen when you try to add it to the dock before the + appears. The grabbing hand should be in the center when you grab from Slingshot too.
For consistency with Plank where app icons get grabbed in the center, but also grabbing a .desktop file in the top left corner like it is now make it go partially out of the screen when you try to add it to the dock before the + appears. The grabbing hand should be in the center when you grab from Slingshot too.