YEAH: Bug found - bug fixed.
There was a bug that was happening while the camera was looking closely to straight down. At first I did not knew what the bug was, but then I saw that it was actually occuring when the selected figure was not entirely in the screen. And then it came. I found the problem: When the figure is not entirely in the screen, it's bounding box is not entirely in the screen, so when you try to move the figure, it's bounding box will project pixel coordinates, that arn't in the visible screen area and that would cause the program to throw an exception, because the invalid coordinates, make the program to use memory, that it's not suppouse to.