Taskbar and Start Menu Properties in Windows Vista and Winodws 7 allows users to change the size of Start Menu by changing the numbers of recent programs to display. However, the text box to enter the value of numbers of recent programs to display in Start Menu can become grayed out and disabled, like figure below.

Start Menu Size Disabled

The value box under the Start Menu Size section when customizing Start Menu is grayed out and disabled due to users have disabled or turned off the option to display recently opened programs.

Recently Used Files and Programs in Start Menu

In Taskbar and Start Menu Properties’ Start Menu tab, under Privacy section, users can set whether or not to save and display the history of recently used or opened programs. If the “Store and display a list of recently opened programs” is unchecked or unticked, it will subsequently also disable the Start Menu Size option box. Thus, enable the option will automatically un-gray the option to set the size or number of recently opened programs listed in Start Menu.