I could put this in the 3rd party apps section, but since I've only tested this on a TomTom ONE, I figured this forum was also appropriate.
There are a number of 3rd party apps that can be installed on the TomTom ONE. When you do, however, the Navcore7 menu icons get a bit messed up when the 3rd part app adds it's icon to the main icon menu.:
For example:
1) You lose the "HELP ME!" icon
2) You get a double "Guided Tours" icon
3) Some of the icons are in different orders
I actually found a cool program that adds an icon to your main menu that allows you to jump back to the Default TomTom menus and then allows you to jump back into the 'custom' menu where their icon is installed....this is all 'on the fly' and you don't need to connect to a computer and you don't need to power off your TomTom.
The program is called MenuTT and is located at tomtomheaven.com:
>>> MenuTT Webpage <<<