ya, mouse pointer problem is there but for this I use usb mouse and connect it using H-E-N and disconnect it before connecting to synergy so mouse pointer will be visible on N900. In my N900 pointer does not invisible after using H-E-N usb mouse don't know this problem is only in my N900 or in everyone's. I have to restart it make it invisible.

There is also a different method to show the mouse pointer on N900 but this one is good because in that method pointer will always visible on N900 screen even if you restart it so That is not looks good.