So, strange behaviour with SmallyMouse 2 and a Teknet wireless USB mouse on my Master running GEM
But if it works with other USB mice I can immediately rule out a hardware issue. So here's where it gets more complex
Most people think there is just one USB mouse protocol, the USB HID mouse protocol, but that's not the case, there are in fact two.
When a PC first boots basic mouse functionality is needed before the OS can load the specific mouse drivers. Therefore there is another protocol called 'boot protocol' which provides basic mouse movement and button reporting. This is used by the PC BIOS (if it support mice). Once the OS is loaded the primary driver takes over - and this might not even be HID compatible... Examples are things like the Logitech Unity mice which have a completely custom driver.
SmallyMouse2 uses the boot protocol for maximum compatibility (as it's mandatory that *every* USB mouse should support it). One of my future requirements is to add functionality that tries USB HID and then falls-back to boot protocol if it's not available. This would mean smallymouse could support scrollwheels and such; I couldn't just implement this instead of boot protocol though - as that would make many advanced wireless mice stop working
So, the most likely explanation is that your mouse doesn't support boot protocol (or has broken support) - you could test this out if you have a PC with mouse support in the BIOS. Either way, it's very naughty if they (the mouse manufacturer) didn't test this correctly!
Is it possible for you to try the BIOS idea? Otherwise the only real way to diagnose the issue is for me to get the same mouse (SmallyMouse2 supports UART debug via the expansion header, so you can dump out mouse information real-time for development).