@Override
	public RowColLocation getDataLocationForCharacterIndex(int characterIndex) {
		if (characterIndex < 0 || characterIndex > attributedString.getText().length()) {
			throw new IllegalArgumentException("columnPosition is out of range: " + characterIndex +
				"; range is [0," + attributedString.getText().length() + "]");
		}
		return new RowColLocation(row, column + characterIndex);
	}
the offset within the field's row where this element begins
Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/field/AbstractTextFieldElement.java