How dissolve vertices actually work?

[Yeremia_Junanto]

I just learned about dissolve vertices, and when I practice it with the default cube, I noticed that some of the vertice behave differently when you dissolve it.

1. They can behave like this (face formed inside the cube)
   
2. Or like this
   
   I want to know why is that happen.

[FedPete]

Dissolving is something else than delete!

Delete throws away the vertice, breaking the mesh. The 3 related edges are then also removed. Which in turn deletes the 3 related faces.

While dissolving a vertice, edge or face. Blender tries to keep the other related parts intact. It erases the vertice, but the 3 related faces are now ‘merged’, because of the missing vertice ( and 3 edges). Resulting in a face with 6 vertices.