Lastest development of my WTC Towers

Here is the latest development of my WTC towers. I used 3 floors to model each tower instead of two, therefore the shape of each tower can be zigzag instead of straight tube.

And there is a problem. Why there is such a warning when I try to modify the sketch although it seems that I can ignore.

Current progress about my Parametric WTC.

Considering that my building is actually constituted by several towers, I make one tower first. This is the ground plan for my one tower. the white is the core and pink are three office space. The office space is placed around the core using a parameter which equates the egress distance to control the distance from the center of the office space to the center of the core.

The center of the pink can only move between the 2 circle's center and the distance between the 2 circles is the egress distance. For some reason, there should be a white square which is the core in the middle, but it disappears.

And then the top floor is different from the bottom floor because I move the office space around the core freely but still within the egress distance. At last these are some variations of the WTC which I am still working on.

When I go through the tutorial, I met a problem, the first snapshot is from the tutorial video and the second is from my file. It is strange that my geometry has black edges displayed and in the tutorial there are no such black edge and the who geometry seems very smooth. Another problem is that when I orbit my sketch, the points disappears and they show up again if I stop orbiting. I am wondering whether it is just a display bug or some display settings are wrong in my digital project.