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Now when you apply this icon you will see that the palette is fixed wherever you zoom. There will probably be parts of the plot which are not filled; this is because our range of contour levels does not cover the whole range of values in the data. Change the list of contour levels so that the whole plot will be covered - you only need to add one number to each end of the level list to do this (or else change the current numbers at the ends of the list).
Updating the Macro
Edit your macro icon again and drop the fixed_t icon into the editor, aiming the drop so that the code is generated above the plot() command. The code to generate the contouring specification will appear, assigned to the variable fixed_t (the variable is always named after the icon that was dropped). Add this to the end of the plot command:
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