Fixcursor is a project mainly written in C, it's free.
Small program to keep the cursor inside the screen in dual-view Linux systems
Small program to keep the cursor inside screen in dual-view Linux systems. Designed for people who use slightly different window placement.
Not perfect -- uses about 2% of CPU all the time. Designed for my 2xfullhd displays aligned like this (was too lazy to write code to fit for all alignments):
| | | Screen 1 | |__| __ | | | Screen 2 | |__|