Linux Gnome Numeric Keypad Disabled [ Mouse keys ]

Q. I'm using Gnome under Ubuntu Linux and my numeric keypad is disabled. Pressing numlock key does not work any more. I'm not able to use numbers or special symbols from numeric keypad. Reboot does not help or using different keyboard does not help. However, numlock only works if I switch to text console by pressing CTRL+ALT+F1. Now, I'm dam sure this is related to X.org or Gnome. How do I fix this problem?

A. This can be easily fixed using Keyboard preference tool. It can modify the autorepeat preferences for your keyboard, and to configure typing break settings. This works as in MS Windows. With this option selected, using Shift with keys on the numerical pad when NumLock is off extends the current selection. With this option unselected, use Shift with keys on the numerical pad to obtain the reverse of the current behaviour for that key. For example, when NumLock is off, the 8 key acts as an up-arrow. Press Shift+8 to type an '8'. Basically, Shift+Numlock can turn on or off mouse keypad. To get rid of this problem simply press Shift+Numlock again.
You can also enable or disable this feature by visiting System > Preferences > Keyboard > Mouse key tab:

Gnome: Keyboard preference tool to control mouse key