Index: openacs-4/packages/calendar/www/cal-item-new.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/calendar/www/cal-item-new.tcl,v
diff -u -r1.41 -r1.41.2.1
--- openacs-4/packages/calendar/www/cal-item-new.tcl	30 Apr 2018 13:54:38 -0000	1.41
+++ openacs-4/packages/calendar/www/cal-item-new.tcl	17 Apr 2019 19:42:59 -0000	1.41.2.1
@@ -16,6 +16,14 @@
     {end_time ""}
     {view "day"}
     {return_url:localurl "./"}
+}  -validate {
+    valid_date -requires { date } {
+        if {$date ne "" } {
+            if {[catch {set date [clock format [clock scan $date] -format "%Y-%m-%d"]} err]} {
+                ad_complain "Your input ($date) is not valid. It has to be in the form YYYY-MM-DD."
+            }
+        }
+    }
 }
 auth::require_login