Product: Synergy 1
Operating system: Windows, macOS, and Linux
When holding a key down while your mouse is on the client, you may notice that the cursor sometimes "rubber bands" or "pings" back to the server computer.
This can be very irritating when you're, for example, holding backspace to delete a few characters or maybe holding the arrow/cursor key down to move around some text. What's happening is that the connection in the background between the server and client breaks momentarily and then recovers, sending the cursor back to the server in the process.
It's caused by a bug in Synergy that occurs when you use two different versions of Synergy together (e.g. 1.14.2 and 1.14.3). Different Synergy versions are meant to be compatible, but unfortunately, that's not always the case. To check what versions you have installed, click Help (on Windows) or Synergy (on macOS) then click About Synergy. The version number is displayed near the bottom left of the window.
How to fix it
The solution is to update Synergy on all of your computers to the latest version of Synergy 1.