Section Challenge Problem

First selecting the edges

But when a cancel with x>edges, this is the result:

Why i cancel the ramp too?
i tried different mode, the only one is to rebuild the face of the ramp.

Where i wrong?

I had the same problem. I believe it is because one or more of the edges you selected were part of the ramps edge.

I solved by switching to face instead of edge when you delete.

i’ve tried that, but nothing happen, nothing cancelled.
hope someone can explain it

Sorry for my english

In 2 minutes i rebuild the the whole pyramid from the start.
I don’t know why, but now is okay.

I would like to know what’s happening.