Python 3.5 Idle3 doesn't work on Xubuntu 16.04

[MR ZenWiz]

I keep getting this:

** IDLE can't import Tkinter.
Your Python may not be configured for Tk. **

I pulled the python down from the Python web site and built it from
there.  I didn't see anything about other packages I'd need to make it
work properly for idle, but both tk ad tcl are installed.

I'm totally new to python, so I have little idea what I'm facing here,
and the google results i get are either for python 2.x or something
that does not work - Fedora/RH/other OS issues answered, but not
Ubuntu.

Any clues welcome.

Thanks.

MR