Very often when I want to move an icon, I want to move more than one. I can drag a box around several icons to select them. Usually, though, when I try to drag the selected icons, nothing happens. Sometimes it seems that you're trying to draw another selection box. On rare occasions, the icons actually move together.
It's as though we can't move multiple things at once, except that sometimes I can.
In general, mouse handling is horrible. Probably 80% or 90% of the time, other than adding an icon, mouse gestures do not do what I want and expect them to do. Most commonly, you're adding lines when I try to move an icon. At least you don't add a line when I try to move multiple icons; you generally don't do anything except un-select.