I'm working with a graphics scene that can contain two types of QGraphicsItems: GraphicNodes and GraphicArcs. (Technically, GraphicNode inherits from QGraphicsRectItem because it made things easier for me but QGraphicsRectItems inherit from QGraphicsItem.) There are several types of GraphicNodes. Their only internal difference is their appearance.

Nodes can be attached to each other using arrows. (I have yet to implement arrow heads.) When I move a node and then try to drag it where it previously was, the arrow is no longer drawn correctly as shown in these screenshots and this blurry video: http://www.youtube.com/watch?v=AQ-bvwUJ9TY

fail.jpg

fail1.jpg

Any thoughts on why this might happen? I didn't use QGraphicsItem's built-in "draggable item" support because I wanted to create a "ghost" preview during dragging. For the bounding rectangle of the arrows, I used the smallest possible rectangle that contains all begin/end points of the line pieces that form the arrow. As long as arrows stay out of the game, everything seems fine.