diff --git a/js/app/views/IntervalUI.js b/js/app/views/IntervalUI.js
index 264b5d6..2c109ab 100644
--- a/js/app/views/IntervalUI.js
+++ b/js/app/views/IntervalUI.js
@@ -125,6 +125,9 @@ Ext.define('amdaUI.IntervalUI', {
 		if (stop != null && start != null) {
             if ( stop <= start ) {
                 form.findField('stopDate').markInvalid('Stop Time  must be after Start Time');
+            } else {
+                if (!form.findField('stopDate').isValid())
+                    form.findField('stopDate').clearInvalid();
             }
 			// compute offset
 			var zoneOffset = stop.getTimezoneOffset() - start.getTimezoneOffset();
--
libgit2 0.21.2