pc and monitor with both hdmi/dvi

monitor is samsung syncmasterp2370hd has vga, dvi, hdmi and composite
inputs. On the pc is an amd video card with vga, dvi and hdmi out.

Primarily I use the dvi but I noticed that if I plug both the dvi and
hdmi into the monitor that the mouse cursor disappears from the
dvi and jumps to the hdmi (monitors remote control source button)

I am guessing that this behavior is normal but if anyone can explain
why it works this way, it would be appreciated.

Also I suspect this is the case on other versions but I am currently
on f19 beta tc2 with current updates.

patrick in socal