I have created a palette in Mathematica v10.0.2, and used the Menu-->Palettes-->Install Palette functionality to successfully install it.
When I choose my palette (from the dropdown menu), rather than automatically running the code, Mathematica simply opens the notebook that contains the palette code. Then I have to perform a Shift-Enter to actually get the palette created.
Question 1: How does WRI get its palettes to auto-evaluate?
Question 2: Does the solution have something to do with this question? How do I automatically evaluate a cell when a notebook is opened?
Question3: Just to have something to work with, how could I get the code below to automatically evaluate after it is installed as a palette?
CreatePalette[OpenerView[{"Open here", "Hello world!"}],
WindowSize -> {200, 200}]