Fixes #20566 (#20768)

mxviteri · mdo · commit 860e07a0e968 · 2016-10-02T21:23:04.000-07:00
diff --git a/scss/_animation.scss b/scss/_animation.scss
@@ -9,12 +9,21 @@
 
 .collapse {
   display: none;
-
   &.in {
     display: block;
   }
-  // tr&.in    { display: table-row; }
-  // tbody&.in { display: table-row-group; }
+}
+
+tr {
+  &.collapse.in {
+    display: table-row;
+  }
+}
+
+tbody {
+  &.collapse.in {
+    display: table-row-group;
+  }
 }
 
 .collapsing {
