I am happily using synergy on my main linux Xubuntu 12.0.3 workstation (server) along with a Windows 7 Ultimate (client) when today I needed to install DirectX to be able to install OBS - Open Broadcast Software. When I clicked (using the server mouse mind you) on the dxwebsetup.exe to install DirectX a dialog box popped up asking if I wanted to allow this executable to modify my computer. When I went to click ok, the mouse was no longer active on the Windows 7 screen, it was on the Linux computer and any attempt to move it over to the windows 7 computer resulted in it not going any further then the edge of the linux computers screen. It was as if the directx installer deactivated synergy. The keyboard and the mouse were no longer able to be used on the windows 7 client. I had to plug in another mouse to the actual windows 7 computer, and click ok. Once I clicked ok and that dialog box disappeared I was once again able to move the mouse from the linux server to the windows client.
Has this happened to anyone else? Very weird and at the same time a major bug, something within dxwebsetup.exe made synergy disabled and my mouse went right back to the server computer. Definitely look into this. I am just lucky i had another mouse laying around. :)