To reproduce:
1. Create a new project.
2. Create new Cube in hierarchy, with a position of (5,5,0) and a scale of(10,1,10)
3. Create a ParticleSystem, with a position of (5,0,0).
4. Enable "Triggers" module, and in Colliders select previously created cube.

Actual result: in Edit mode, simulation is ignoring newly selected Collider.
Expected result: Particles would be destroyed in the Simulation when they enter the Collider.

Reproducible: 2017.2.0a4, 2017.2.0b1
Not reproducible: 5.6.2f1, 2017.1.0b10, 2017.2.0a3

Workaround: Play scene. Stop. Now it's simulated correctly.
Other workaround: Save project, and reopen it.