the SQUARE 'window plan' and 'roof/wall junction' icons are details that YOU have created from drawn plan and section window content respectively.
the CIRCULAR wall/floor junction is an independent detail created out of the 'Tools' menu rather than from existing drawn content.
if they have borders then they have been referred to with a detail marker somewhere within the project. borderless (square or circle) icons are details with no reference marker. i.e. not yet in use.
HTH
~/archiben
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