I use Blender 2.9. I am trying to make this stand alone cooker top. The edges were working fine. I then selected the little edge we see at the top and 'Edge Slide' it to move it lower along the 2 vertical edges besides (I though the edge would 'slide', but it formed a new edge and slid it along, exactly as I wanted it to. Happy me.)
But when I try to do the same with the other little edge (the one below),I noticed that the edge got selected as dotted lines, and I could not move or slide it. And so were the other edges(as shown in the picture below).Rest of the edges on the face(The diagonal edges, the middle 2 vertical ones, and the happy edge) work fine.
I'm new to Blender, this could be something simple. Why are the edges misbehaving? What's with the dotted selection? Also, what would be the most effective way to slide the edge, making a new face in between? (Like I did on the top but I don't know how I did it)