I am new to Blender (2.9) and have some Problems Editing Meshes. I am repairing a model which I built some time ago in ArchiCAT and I'm trying to join Walls and so on. Now im editing some meshes and somehow they appear wrong. It looks like the faces are broken. Also the edges are not highlighted as you see on the picture. I think thats a simple problem to solve but i cant find it.
What's the problem if the edges of the model/mesh look like in the screenshot?