Steps:
1. Create particle system
2. In Shape Module, select Mesh, assign a mesh e.g. cylinder
3. In scene view, you should see the wireframe of the cylinder
4. Rotate / zoom the view and observe

Actual result:
The wireframe is not stably visible. Part of it disappear at some angle or totally invisible when zoom out

Expected result:
The wireframe should always be there clearly visible

Reproduced with:
2017.1.0b1 (a29fc4a7eb25)

Not reproduced with:
2017.1.0a6