@Override
	public boolean isValid(int row, int col) {

		if (row != 0) {
			return false;
		}
		if ((col < 0) || (col > numCols - 1)) {
			return false;
		}
		return true;
	}
@see docking.widgets.fieldpanel.field.Field#isValid(int, int)
Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/field/SimpleTextField.java