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PTN·03·001

The Modal

Earns its place — narrowly documented

A modal is an interruption with a door policy: it seizes focus, dims the world behind it, and refuses to let anything continue until its one question is resolved. That seizure is the entire design — and the entire risk. Used precisely, it is the interface saying this cannot wait. Used habitually, it is the interface saying we don't trust you to notice things, forty times a day.

the escape hatch — never optional scrim — the dimmed world
FIG 03·001 — the door policy, drawn.
AnatomyScrim (the dimmed world) · container · title stating the decision · the content of the decision · a primary action, a safe exit, and — non-negotiably — an escape hatch (Esc, scrim-click, or an explicit close) that maps to the safe exit.

Use when

  • A decision must be resolved before anything else can continue
  • The action is destructive and the cost of a mis-click exceeds the cost of interruption
  • The task is short, self-contained, and loses meaning outside its context

Avoid when

  • The content could simply live on the page behind it
  • The task involves reference to the page you just hid
  • It fires on arrival — a modal nobody asked for is an ad
  • An undo would make the confirmation unnecessary
States & accessFocus moves into the dialog and is trapped there; Esc closes; focus returns to the trigger on dismissal; the page behind is inert to assistive tech (role="dialog", aria-modal). A modal that loses the keyboard has failed at the primitive level, whatever it looks like.
HistoryModal dialogs predate the GUI — the concept ships with early windowing systems (Smalltalk, Lisa/Macintosh era); the term "modal" names the mode error it risks.
SpecimensOS file-delete confirmations (earned) · newsletter pop-ups on arrival (unearned) · payment 3-D Secure (imported, unloved).
Principle at stakeFeedback & mode — see the Stairwell; when the seizure isn't justified, see the Basement.
SourcesPlatform primary sources (Apple HIG, Material dialogs guidance); Nielsen on interruption cost. Specimens own-captured, dated.

Why documented: The ARIA Authoring Practices specify the dialog’s focus trap, Escape, and focus return. The access requirements are not opinion.