As you know MegaDrum is a USB MIDI Class compliant device. This essentially means that all modern OSs come with USB MIDI drivers built-in and you don't need to install any additional drivers.
You also know that the Windows USB MIDI driver has at least one limitation - only one MIDI application at any given time can access USB MIDI port. As a way of workaround I implement 2 USB MIDI ports in MegaDrum firmware so that you could run MDM to control MegaDrum and one other MIDI application at the same time.
Apparently there are some (free?) Windows USB MIDI drivers out there which don't have this limitation. One of the examples is KORG USB MIDI Driver.
To test it, I followed a link from http://www.korg.com/us/news/2014/0218/ to download USA_DrvTools_e(1.14_r12).zip (selected "tactile" from the list of devices) and installed it.
A warning: I'm not sure about if it is allowed by KORG to use this driver with non-KORG devices, so I personally will uninstall it after the test.
After the installation I told Windows in Device Manager to use "KORG Inc.-> KORG MIDI Device" for MegaDrum. After this MegaDrum is shown as KORG MIDI Device in Device Manager.
After this I tried to access the same MegaDrum USB MIDI port from MIDI-OX and MDM. And indeed I could access the port at the same time without any conflicts - MDM was happily sending/receiving data to/from MegaDrum and MIDI-OX was showing the flow of data!
There are apparently claims that this driver has also lower latency then the Windows built-in USB MIDI driver but I have not tested it.
I also noticed that the KORG's driver is free from one of Windows USB MIDI driver bug (for which I have a workaround in the firmware as well so it doesn't effect MegaDrum).