Click the field — the blinking blue line between letters is the insertion caret
Insertion Caret (Insertion Point)
/ NSTextView.insertionPointColor · NSTextView.selectedRange /
also called insertion point, text caret, text cursor, typing caret
“The blinking line where I am typing” is the insertion caret, also called the insertion point. It sits inside editable text and marks where the next character will appear. It is not the I-beam mouse pointer, which moves with the mouse, or the animated dots that show another person is typing.
If you called it…
…you meant a insertion caret (insertion point).
Anatomy — every part, named
- 1Insertion caret
NSTextView.insertionPointColorThe thin blinking line between characters is the insertion caret.
Prompt — paste into your agent
Show a text insertion caret (AppKit: NSTextView.insertionPointColor) as the thin blinking vertical line at the zero-length selectedRange where the next typed character will appear; on the web, style the same pixel with CSS caret-color.
Debug prompt — when it misbehaves
Paste this, then describe what you’re seeing — it hands your agent the classic failure modes to rule out first.
Debug my text insertion caret (NSTextView.insertionPointColor, selectedRange). Rule out: the field is not first responder; the selection has nonzero length so there is no single insertion point; custom text drawing covers the caret; the caret color has no contrast; focus is being moved by another view. The symptom:
In code
The exact names this thing goes by in code — each row is one framework’s word for it. Use the row that matches your project (or paste it into your prompt).
| AppKit | NSTextView.insertionPointColor | |
| AppKit | NSTextView.selectedRange | a zero-length selection is the insertion point |
| AppKit | NSTextView.drawInsertionPoint(in:color:turnedOn:) | |
| CSS | caret-color |