The three kinds of data a cell can hold, and why a command can behave differently on each. Many "why did this do nothing?" questions come down to which kind of data is selected. A cell holds one of three kinds: grid data (typed, pasted or imported — no restrictions), a preview pin (a live, read-only page of a query result) or a static pin (the full query result, loaded once and still refreshable from its SQL). Throughout this documentation a "Behaviour by data mode" table states what a command does on each.
This site needs JavaScript for the full experience. Every page above is reachable without it.