With Yosemite pop-over doesn't work when holding keys down anymore I always used the accented character pop-over menu often, by holding a key for a second or two.  Now, with Yosemite suddenly all I get is something like:


  Resumeeeeeeeeeeeeeeeeeeeeeeeeee


When I want the chance to type:


  Resumé


I feel like I'm missing something obvious.
Resume



Maybe it is disabled for some reason ?

defaults write -g ApplePressAndHoldEnabled -bool false


to enable copy paste following in your Terminal app located in the utility folder.

defaults write -g ApplePressAndHoldEnabled -bool true