Edit: This is apparently only a problem on a mac running OSX.

I am trying to use the ['stretchText'](http://mathematica.stackexchange.com/questions/4374/scale-insetted-characters-to-plot/4387#4387) function by Jens. But when I use it in manipulate, the output keeps updating without changing anything.

This is the simplest example in which the problems occurs:

    Manipulate[
     choice;

     Graphics[{
       stretchText["{", {0, 0}, {.1, 1}]
       }],
     
     {{choice, "b"}, {"a", "b"}},
     
     Initialization -> {
       stretchText[char_, pos_, scale_, angle_ : 0] := 
         Module[{g, coords, xMin, xMax, yMin, yMax}, 
          g = First@
            First@ImportString[ExportString[char, "PDF"], 
              "TextOutlines" -> True]; 
          coords = 
           Apply[Join, 
            Cases[g, FilledCurve[___, p_] :> Flatten[p, 1], 
             Infinity]]; {{xMin, xMax}, {yMin, yMax}} = 
           Map[{Min[#], Max[#]} &[#] &, Transpose[coords]]; 
          Rotate[Inset[
            Graphics[g, PlotRange -> {{xMin, xMax}, {yMin, yMax}}, 
             If[ListQ[scale], AspectRatio -> Full, 
              AspectRatio -> Automatic]], pos, {xMin, yMin}, scale], 
           angle]];
       }]

What can I do to stop the endless updating?