Along with several bug fixes and other enhancements, today's update to Brewtility includes functionality for specifying a partial boil when creating a recipe.
So, when creating a partial mash or extract recipe you'll now see a field labeled "Boil Size." (Shown below)
Setting the boil size equal to the batch size would indicate a full boil and the rest of the recipe will be unchanged. However, if you're an extract or partial mash brewer and you only boil, say, 3 gallons of liquid and then top off to 5 gallons after the boil, you'd set the Batch Size to 5 gallons and the Boil...