public int overColumnDivider(int x) {
		int divider = getColumnDividerWidth();
		int count = mColumns.size() - 1;
		int pos = 0;
		for (int i = 0; i < count; i++) {
			TreeColumn column = mColumns.get(i);
			pos += column.getWidth();
			if (x >= pos - HIT_SLOP && x <= pos + HIT_SLOP) {
				return i;
			}
			pos += divider;
		}
		return -1;
	}