The touchpad is slow to respond after using the keyboard. There is a lag time before the mouse will respond to the TouchPad's input. When testing using an external mouse, the mouse input works fine.
Ensure you have the latest Synaptics TouchPad driver for your machine. Check for the latest version here
If the support's site version is newer than what you have in the system, do uninstall previous version first, reboot then only install the latest one which you have downloaded. Test the TouchPad and see if it working properly, if problem still persist, follow the step provided below to change the settings.
Click Control Panel
Select Device Settings tab
6. Expand the Pointing tab, and find Palm Check:
7. Click the slider and slide the bar all the way to the left to reduce the sensitivity.