In case you need to lock your cursor on the current screen (monitor), please follow instructions below:
1. Based on Standard Configuration File:
1. Open Synergy Server.
2. Click on Configure Server
3. Click on Hotkeys
4. Under Hokeys add new Hotkey
5. Then click on Actions - New
6. And set "Lock cursor to screen" to "Off"
7. Hit Ok and Apply.
2. Based on Manual Configuration File:
1. Open your Configuration File
2. And add keystroke(Control+1) = lockCursorToScreen(off) to your confi file as per example below: