Center new windows

[richard.a.charts.1]

Hi,
I have a fairly quick question that I haven't been able find the answer
for.  When opening a new window, how can I force it to open in the center
of the screen?

I have searched through old messages but most are over 2 years old and I
am wondering if there has been changes for the better?



On a small side note:
How does geometry work with a given widget?  Whenever I try to use it,
Python says that some class has no instance of geometry or withdraw or
others for that matter.
Thanks