Position and size bug with "Group in dynamic panels".
When a group of items are grouped in dynamic panels, the new dynamic panel is 1 pixel (width and height) less than the original group size, and the group is at the relative position (-1,-1).
To reproduce it :
Place an 100*100 image at 50,50 position, right click > convert to dynamic panel.
Now the dynamic panel is 99*99 at 50,50 position, and the image is at -1,-1 relative position in the dynamic panel, so 49,49 absolute position.