This variable has meaning only on systems that support a mouse. It controls the double-click rate on systems that do not control it themselves.
Specify the maximum time (in hundredths of a second) allowed between two clicks that are to be interpreted as a double-click. For example, if DOUBLE_CLICK_TIME were set to 75 (three-quarters of a second), then any two clicks that occur at least that close together would be considered a double-click rather than two single clicks.
The default value is 50 (one-half of a second).