Fix problem with the wrong minicalendars being shown in the month vie…

…w when you're at the end of the month (eg Aug 31) and the next month has fewer days than the current one.

web/js/datepicker.js.php

@@ -75,6 +75,12 @@ function monthStart(date) {
 
 function monthEnd(date) {
   var d = new Date(date);
+  <?php
+  // Set the date to the first of the month, because otherwise we will
+  // advance by two months when incrementing the month below if we're at the
+  // end of the month and the next month has fewer days than this one.
+  ?>
+  d.setDate(1);
   d.setMonth(d.getMonth() + 1);
   d.setDate(0);
   return d.toISOString().split('T')[0];