I've used Multiplicity for many years connecting all my Windows devices. I have found it the best of software solutions.
However, there is one behavior that has driven many users crazy. All of a sudden when you are typing in the computer you are working on, the keyboard strokes will stop working. Over the years many different sources have been identified as the possible issue like antivirus programs, etc.
What I have found is that when you run your browser (in my case I primarily use Firefox) on 2 or more computers with Multiplicity installed, lets say PC1 and PC2, if you are working on PC1's browser and all of a sudden its stops typing (even though you had your mouse over this screen - that is PC1), because on PC2 the browser takes (via non-user prompted) focus of the mouse it effectively has stopped your ability to type in PC1.
So to repeat another way, when a user is using Multiplicity to be PC1, their ability to type becomes erratic because the browser on PC2 (or any other PC using Multiplicity) has taken over the focus.
Stardock needs to figure out a way to prevent this. Only user movements should move the focus.
Right now the only solution when PC1 starts to not be able to type correctly, is to go to PC2 and stop the focus on the browser by clicking on a non-browser window. When that happens, when you go back to PC1 you are able to type normally without issues.