diff --git a/addons/web/static/src/css/base.css b/addons/web/static/src/css/base.css
index 7f68261d758..b8f5a998cd7 100644
--- a/addons/web/static/src/css/base.css
+++ b/addons/web/static/src/css/base.css
@@ -1405,6 +1405,7 @@
 }
 .openerp .oe_form_sheetbg {
   padding: 16px 0;
+  position: relative;
 }
 .openerp .oe_form_sheet_width {
   min-width: 650px;
diff --git a/addons/web/static/src/css/base.sass b/addons/web/static/src/css/base.sass
index b335a122640..eee7739b3f6 100644
--- a/addons/web/static/src/css/base.sass
+++ b/addons/web/static/src/css/base.sass
@@ -1263,6 +1263,7 @@ $sheet-padding: 16px
             margin: 0
     .oe_form_sheetbg
         padding: 16px 0
+        position: relative
     .oe_form_sheet_width
         min-width: 650px
         max-width: $sheet-max-width