Error while load sharedString from file with merged cells

[baminmru]

test.xlsx

error found in function:
internal SharedStrings(ZipArchive archive)

After load string sequence is worng if Excel file contain vertically merged cells.

I make some changes like this:
foreach (XElement si in document.Descendants().Where(d => d.Name.LocalName == "si") )
{
String s;
s = "";
foreach (String X in si.Descendants().Where(d => d.Name.LocalName == "t"))
{
if (s != "") s += " ";
s = s + X;
}
int i = AddString(s);
System.Diagnostics.Debug.Print(s + ":" + i.ToString());
}