I have a Windows 8 desktop, Mac Mini, two monitors, and a KVM.
The KVM has two settings:
Monitor 1 -> Windows 8 desktop Monitor 2 -> Windows 8 desktop USB Mouse -> Windows 8 desktop USB Keyboard -> Windows 8 desktop
Monitor 1 -> Windows 8 desktop Monitor 2 -> Mac Mini USB Mouse -> Mac Mini USB Keyboard -> Mac Mini
When using setting 2, I want to be able to share my mouse and keyboard between both my Windows 8 Desktop and Mac Mini. To accomplish this I am using ShareMouse.
My problem is that whenever I switch the KVM from Setting 1 to Setting 2, the mouse cursor disappears from my Windows 8 desktop. I am able to move the cursor from my Mac Mini (on Monitor 2) towards Windows 8 (on Monitor 1) and share mouse reacts appropriately (it displays transition animations and transfers keyboard/mouse focus onto the Windows 8 desktop). Unfortunately, the cursor is completely invisible in Windows 8. I am able to move the invisible cursor and click and interact as if the cursor was there, but the actual cursor graphic isn't shown.
So, whenever Windows 8 detects that the USB mouse is unplugged, it removes the cursor from the display. Presumably, this is done to accommodate touch input. Apparently there is an option to enable the cursor to appear where the screen is touched in the "Pen and Touch" section of control panel, but I obviously don't have that section since I'm using a desktop.
I've looked around and found a few other people with similar issues. It seems they weren't able to find a software solution. What they ended up doing was plugging in a wireless USB mouse receiver (without actually connecting a mouse). Believe it or not, I don't have an extra mouse (or wireless receiver) right now plus I feel like there should be a software solution to this problem.