Registry Entries

HKEY_LOCAL_MACHINE
\System
\CurrentControlSet
\Services
\EloTouchscreen
\enum
\NTSerial0
\MMStub
\Security
\monmouse
\Security

The touchscreen parameters are in the \EloTouchscreen area. 

The following additional keys control the double-click area sensitivity:

HKEY_CURRENT_USER
\ControlPanel
\Mouse
\DoubleClickHeight
\DoubleClickWidth