There are a simple method to open and close CD/DVD ROM (or any disk drive) tray with a single mouse click.
To eject CD ROM Tray
Just type eject on terminal
To close CD ROM Tray
Type eject -t on terminal.
If you make two launcher using this commands. Change icon as your desire and add them on top panel, then it would be very curious for any windows user.
You can use eject /dev/sr1 command to specify a CD/ DVD drive if you have more then one.
Can't understand yet? Please inform me by a comment I will explain you details. You can check 'eject --help' man page for more information.