title: Qt: Sorting is wrong when using QSortFilterProxyModel on number strings and getting wrong column text
body: <p>i have simple model view treeview with QSortFilterProxyModel proxy to sort the columns and QStandardItemModel as the model<br>
  in each columns there are string that gets sorted fine but in columns that contains number ( as strings ) the sorting wrong .<br>
  say i have 9,12,1 (each number in different column when i sort them im getting 1,12,9 or 12,1,9 but never in the right order .
  like 1,9,12 or 12,9,1 why ?<br>
  also i notice that when i sort row by column , when i try to get the new column text with    <code>m_model-&gt;item(iSelectedRow,0)-&gt;text();</code><br>
  im getting the initial column text but never the new sorted column text. why ?</p>