diff --git a/x-pack/plugins/watcher/public/components/expression_builder/components/expression_popover/expression_popover.html b/x-pack/plugins/watcher/public/components/expression_builder/components/expression_popover/expression_popover.html
index 5de922e1d3b6d..2dea0d67c3a9a 100644
--- a/x-pack/plugins/watcher/public/components/expression_builder/components/expression_popover/expression_popover.html
+++ b/x-pack/plugins/watcher/public/components/expression_builder/components/expression_popover/expression_popover.html
@@ -1,4 +1,6 @@
-<div class="euiPanel euiPopover__panel euiPopover__panel--bottom watcherExpressionPopover">
+<div 
+  class="kuiPanelSimple kuiPopover__panel"
+>
   <div class="kuiPopoverTitle">
     {{ expressionPopover.popoverTitle }}
   </div>