diff --git a/lib/timeline/Stack.js b/lib/timeline/Stack.js
index ab921893..1893c07e 100644
--- a/lib/timeline/Stack.js
+++ b/lib/timeline/Stack.js
@@ -177,7 +177,7 @@ exports.collision = function(a, b, margin, rtl) {
  */
 exports.collisionByTimes = function(a, b) {
   return (
-    (a.start < b.start && a.end > b.start && a.top < (b.top + b.height) && (a.top + a.height) > b.top ) ||
-    (b.start < a.start && b.end > a.start && b.top < (a.top + a.height) && (b.top + b.height) > a.top )
+    (a.start <= b.start && a.end >= b.start && a.top < (b.top + b.height) && (a.top + a.height) > b.top ) ||
+    (b.start <= a.start && b.end >= a.start && b.top < (a.top + a.height) && (b.top + b.height) > a.top )
   )
 }
\ No newline at end of file