There are several ways to accomplish this.  First, the phone application is always running in the background and monitoring the Green/Red Phone Keys.  If you are using a GSM phone, you can terminate the phone application and thus never see this popup.  However, if you are using a CDMA phone, you can't terminate the phone application since this will also disable any data connections made via WLAN. Another alternative is to create custom .rmt and .sct Keymap files for the device which disable the key. The Green Phone Key is the F14 Key, while the Red Phone Key is the F15 Key.  From an application standpoint, you can use either a keyboard hook to ignore the Green Key, or add the green key as a hot key to your application.