I am editing the floor boundary and there are constraints on some of the sketch lines. I am wondering why I am not seeing padlock icons and how to identify to which element any particular sketch line is constraint.
Just curious here -- would switching to one of the plan views make a difference when editing the slab?
I don't believe switching to a plan view will make a difference. My guess is that there is something else in the model that is locking the floor boundary in its place. For example, there could be a dimension from the floor edge to a grid that is locked, or an element that the floor edge is aligned and locked to. When editing the boundary of the floor, the padlocks from those external constraints don't show up. To try and identify what is providing the constraint, try getting out of the Edit Floor Boundary command and selecting the floor. It should highlight any padlocks that apply to the floor.