public boolean isOpenBetween(int startRow, int endRow) {
		Entry<Integer, V> ceilingEntry = verticesByRow.ceilingEntry(startRow);
		if (ceilingEntry == null) {
			return true;
		}
		int nextRow = ceilingEntry.getKey();
		return nextRow > endRow;
	}
The grid index of this column (0, 1...n) for the number of columns
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/Column.java