I am trying to setup a dual boxing with two clients on one machine but I am having a problem with Keyclone.

If I keep "focus follows mouse" off, moving from one window to another is instant, and even clicking to activate the windows doesn't delay anything (working as intended).
However, if I keep "focus follows mouse" on, when I move to the inactive window, the mouse freezes for 1-3 seconds (I think, however quite a long time) while still having the old window active and then suddendly appears in the other window. This looks kinda annoying.
I have asked in chat and someone said that the switch should be almost instant, so I have a problem. What can I do?
Do you need any detail about my configuration?

Thanks in advance!