I'm having issues with trying to do polygon modeling. When I went into Vertex Mode and selected vertices to model, it selects a whole area highlighted in yellow, orange, red, and black, instead of staying in the blue wireframe where the selected polygons are yellow.
Here's a screenshot of what I'm trying to explain...

The results are do not act the same so I know I'm in a different mode. I do not know what it is called, what it does, nor how to get back into the normal editing vertices mode.
Please help! Thanks!