Strange, when Cubase has the focus and I select (e.g) f3, I get the Windows default f3 function - a display of my current opened windows, rather than the Mixer appearing.
Anyone know how to fix this?
thank you all
Z
Sorry, I don’t have an answer but I was wondering if you ever figured this out?
If not… at least your question is bumped. 
Regards 
Use fn+ F3…
Better still, if using a PC, go into your BIOS and change default behaviour of keyboard there…
This is a common issue with the qwerty keyboard configured to give preference to Windows Functions.
Tried the BIOS (X99) no sign of any keyboard tweaks. But I have solved this a minute ago.
I have found out that this is specific to one keyboard. Logitech K400. I plugged in another kb and it works fine f3 bring up the mixer, etc.
So, I went to Logitech and downloaded “Logitech Options”, then found an option " Use f1-12 as standard function keys. This worked
It appears that some keyboards do this! I have no idea how it started mine was just fine before!
thank you
Z