Can you try executing the following command (fix the paths as necessary, but leave all the quotes where they are):

"C:\Program Files (x86)\Python 3.5\python.exe" -m idlelib "C:\test.py"

That's what should be launched by the menu, with a minor change to use python.exe instead of pythonw.exe to show up any errors you are hitting.

I couldn't reproduce the issue on Windows 10, but when I'm back at work I'll try with some other OS versions.