Why does one of the faces show dotted in editmode? I just started blender a few days ago and I noticed that when making faces, they sometimes have this dotted texture compared to the generic smooth texture. I have been having difficulties with this and was wondering why these dotted faces are different from the regular faces, how do I get rid of them and what are the advantages of using them?

This is my image:


Thank you!
The last selected faces is known as the Active Face and draws with a Stipple overlay (dots),

This is used to determine which texture to show in the image window, since its possible to UV map multiple images from a single mesh.