System Information
Windows 7 Pro SP1, NVIDIA GeForce GT 750M

Blender Version
Broken: 2.76 8c84a18 AMD64
Worked: don't know

Short description of error
When you add a boolean modifier to a mesh, let's call it A, and the modifier "Object" operand, let's call it B, is a child of the mesh itself (that is, B is child of A), the result of the modifier does not display in the viewport in the following two cases:

1. When you first load the project.
2. When you enter and then exit edit mode on child object B.

To have the modifier display, you have to either move the child or enter/exit edit mode on the parent or disable/enable the modifier, but when you enter/exit edit mode on the child again, the problem reappears.

Exact steps for others to reproduce the error

1. Load the attached .blend file, and you can see that the cube is not being "cut" by the child sphere, as it should.
2. Press TAB (enter edit mode on the sphere) and the bool modifier starts displaying.
3. Press TAB again (exit edit mode) and the bool modifier does not display anymore.
4. Grab and move the child sphere, and the modifier starts displaying
5. Press TAB twice (enter/exit edit mode on the sphere), and again the modifier does not display anymore.