Inserting rows with colspan can fake the total number of columns then the title, subtitle and date are not extended to all the columns.

Steps to reproduce:

1. Open the script tool
2. Execute the following script:

   var report = Report.create("Mon rapport");
   var header1 = report.addHeader();
   header1.addColumn("Titre", 1, 2);
   header1.addColumn("Code", 1, 2);
   header1.addColumn("Volume horaire", 3);
   report.addHeader("CM", "TD", "TP");
   report.print();

   

Note that rowspan can do the same by shifting columns.

var report = Report.create("Mon rapport");
var header1 = report.addHeader();
header1.addColumn("Titre", 1, 2);
header1.addColumn("Code", 1, 2);
header1.addColumn("Volume horaire");
report.addHeader("CM", "TD", "TP");
report.print();