Q: older Apple display not working with new Macbook Pro

I just got a new Macbook Pro (15", 2.5 GHz, 16 GBram, os 10.9.4) and I am suffering terribly from growing pains. My current issue is that I have an Apple 27" cinema display from about 2010 with the mini display port (it has a triple for the computer, AC, USB and mini-display). I got an adapter for the AC, and was told that the mini display port will work in the thunderbolt slot—and it does, to a point. It fits, and the screen on the monitor comes up (though oddly, it still shows a desktop picture no longer configured on the new Mac, and the menu bar at the top is greyed out). The mouse will go to it, whether using both screens or just the display screen, but whenever I put a window (from any program, textedit, photoshop, etc) over in to the display window, the screen turns black. The mouse can still be seen, but the rest of the screen is completely black and will not come back up until the window or windows are moved back to the computer's display.

Can anyone help me with this one? Not anxious to plunk down $1,000 on a new display when my current one is in fine condition—so I think...

Thanks

Shelley