Index: announcement-tool/tool/src/java/org/sakaiproject/announcement/tool/AnnouncementAction.java
===================================================================
--- announcement-tool/tool/src/java/org/sakaiproject/announcement/tool/AnnouncementAction.java	(revision 46231)
+++ announcement-tool/tool/src/java/org/sakaiproject/announcement/tool/AnnouncementAction.java	(working copy)
@@ -4109,18 +4109,31 @@
 
 		doUpdateDisplayOptions(runData, state, sstate);
 
-		// We're omitting processing of the "showAnnouncementBody" since these
-		// options are currently mutually exclusive.
-
-		// commit the change
-		saveOptions();
-
-		// Turn the observer back on.
-		enableObserver(sstate, true);
-
-		state.setStatus(null);
-
-		sstate.removeAttribute(STATE_MODE);
+		/*
+		 * SAK-13116 If we are in the synoptic view, we want some validation so
+		 * that is not possible to set the Number of Announcements to greater 
+		 * than 20, since only 20 will be displayed no matter what.
+		 */
+		if (isSynopticTool() && state.getDisplayOptions().getNumberOfAnnouncements() > 20) 
+		{
+			addAlert(sstate, rb.getFormattedMessage("custom.numberann.sizeerror", new Object[] { 20 }));
+		}
+		else 
+		{
+			// We're omitting processing of the "showAnnouncementBody" since these
+			// options are currently mutually exclusive.
+			
+	
+			// commit the change
+			saveOptions();
+	
+			// Turn the observer back on.
+			enableObserver(sstate, true);
+	
+			state.setStatus(null);
+	
+			sstate.removeAttribute(STATE_MODE);
+		}
 	}
 
 	/*
Index: announcement-tool/tool/src/bundle/announcement.properties
===================================================================
--- announcement-tool/tool/src/bundle/announcement.properties	(revision 46231)
+++ announcement-tool/tool/src/bundle/announcement.properties	(working copy)
@@ -129,6 +129,7 @@
 custom.number = Number of days in the past
 custom.numbann = Number of announcements 
 custom.options = Options
+custom.numberann.sizeerror = The number of announcements must be {0} or less.
 
 custom.sortab = Sortable table view
 custom.sortabbod = Sortable table view with announcement body