If you're using a Wacom and your experiencing writing lag or writing not appearing, you might need to turn Windows Ink on or off (depending on your specific setup).
Install the latest Wacom tablet drivers.
Launch the Wacom Tablet Properties application.
Select your Tablet.
Under Tool, select your pen.
Under Application, select All.
Navigate to the Mapping tab.
Check or uncheck "Use Windows Ink".
Refresh the page.