The div has the class .band__section (and its settings) applied to it, yet it’s not showing up in the selector area and the div in question still has the grey dotted outline showing…
As far as I know. When you don’t apply any height or width settings - it’s on default has this grey outlined box with height (for easier visual indentification).
I should be gone when you will put any element inside or change height/width
This is very true. A div will keep the placeholder dotted border in the Designer in building mode, as long as it doesn’t have dimensions. Dimensions could be set by their content, or defined with width, height, or padding, or inherited from parents (like a flex parent).