some accented chars double width

[Dan Jacobson]

In uxterm, all these are single width and look fine,
āáǎàēéěèīíǐìōóǒòūúǔùǖǘǚǜüê
but in firefox and emacs, some are double width.
How might I remedy this? How can I tell fontcongig or whatever to
first try Latin extended B before Chinese?
Or maybe I need to apt-get install more fonts.