It is often necessary to hide a mesh to have a look at the particles underneath because this helps to evaluate the accuracy of the mesh or simply makes other parts of the scene visible. The "Display" tab provides various settings to draw the mesh the way you want.
NEW SCREENSHOT
Visible
You can hide the mesh by changing this option from “Yes” to “No”.
...
This option makes it impossible to select polygons from invisible parts of the mesh.
Extension draft
When the mesh's extension feature is active you will see a grid (number of tiles in U and V direction), a square with a solid line (“@ Fall Off from”), and a square with a dashed line (“@ Fall Off to”). To hide these elements, choose “No”. You do not have to create a mesh to see this grid – it is enough to enable Boundaries > @ extension.