I was dragging say a dozen images around a contact sheet in arangement mode (EeePC netbook, WinXP, PM ver 4.6.1) and I notused that some times the selection starts to behave strange. I move a lot of similar images (say the image has mostly yellow subject in the frame) beside each other, than I select them to move them next to another similar group of images. I drag the images selected and when I drop them not all of them is selected but some other images get selected like if the selection would fall apart or it would mistake what was originally selected.
It seems usually happen when most of the selection is outside the screen before I start dragging them.
I will try to document it with some screenshots to help understand the problem.