diff --git a/packages/overlayscrollbars/src/styles/sizeobserver.scss b/packages/overlayscrollbars/src/styles/sizeobserver.scss
index 52731eb..a9924fc 100644
--- a/packages/overlayscrollbars/src/styles/sizeobserver.scss
+++ b/packages/overlayscrollbars/src/styles/sizeobserver.scss
@@ -26,6 +26,7 @@ $scrollbar-cushion: 100px;
   height: 100%;
   width: 100%;
   z-index: -1;
+  contain: strict;
 }
 
 .os-size-observer-appear {
diff --git a/packages/overlayscrollbars/src/styles/trinsicobserver.scss b/packages/overlayscrollbars/src/styles/trinsicobserver.scss
index ec2dd46..5c7e936 100644
--- a/packages/overlayscrollbars/src/styles/trinsicobserver.scss
+++ b/packages/overlayscrollbars/src/styles/trinsicobserver.scss
@@ -11,6 +11,7 @@
   z-index: -1;
   height: 0;
   top: calc(-100% + 1px);
+  contain: strict;
 
   &:not(:empty) {
     height: calc(100% + 1px);