How to define part of a Manipulate control variable definition to reduce code duplication

Question

This is a little related to this question

Define control as variable in Mathematica

But the above question did not answer my problem, as it talks about the f

Answer 1

I was going to give a solution almost the same as Leonid's and use With to insert the code, but he beat me to it, so here's an alternative way. Define a dynamic local function using ControlType -> None that does your styling:

Manipulate[Plot[{f, g + 1}, {x, -1, 1}], 
 Dynamic[Grid[{{Style["f(x)="], pu[f]}, 
       {Style["g(x)="], pu[g]}}]], 
{{pu, Function[{f}, PopupMenu[Dynamic[f], {x, x^2, x^3}, ImageSize -> Tiny], 
        HoldFirst]}, None}]

By the way, the Style[] in Style["f(x)="] is redundant, as you are not actually setting any styles...