Ok, I tried swamped suggestion (replacing setactivecontrol with setactiveinput). First starting ddm.exe, then switch to the Apple machine using ddm.exe /setactiveinput mDP, then while the input is on mDP, executing ddm.exe /setactiveinput DP on the Windows machine. The input does NOT get switched to DP. Even worse, when I try to get the logging with shift-right click the ddm is crashing.
I very much like the input from an Dell programmer that knows about ddm inner workings. It seems to me that ddm cannot send it's commands to the monitor when the active input is on a computer that does not support it.
Sorry, that was a typo which should have read "SetActiveInput". But you should do the following:
1. Start DDM on the WinPC and leave it running with "ddm.exe" (no parameters)
2. Execute the following command-line from the WinPC: "ddm.exe /setactiveinput mDP"
(this should switch the input to the Mac)
3. Send the following command-line from the Mac to the WinPC: "ddm.exe /setactiveinput DP"
(this should, but fails to switch input back to the WinPC)
4. On the WinPC, save the diagnostic report and post it
(this will have a record of step 3, if it was received from the Mac and processed)
Simply put your Mac to "sleep" logically (via apple menu) or physically (via the power button, and the K&M will toggle back to your PC...