diff --git a/.changeset/gentle-bikes-relax.md b/.changeset/gentle-bikes-relax.md
new file mode 100644
index 0000000000..7a4aeda5f8
--- /dev/null
+++ b/.changeset/gentle-bikes-relax.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs-module-addons-contrib': patch
+---
+
+ExpandableCollapse Techdocs Addon was breaking native sidebar collapse on Firefox
diff --git a/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/even-deeper/index.md b/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/even-deeper/index.md
new file mode 100644
index 0000000000..33f63ea079
--- /dev/null
+++ b/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/even-deeper/index.md
@@ -0,0 +1,9 @@
+# Deeper Nav
+
+Useful to test ExpandableNavigationAddon!
+
+## I'm in too deep!
+
+## And I'm trying to keep
+
+### ...up above my head
diff --git a/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/index.md b/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/index.md
new file mode 100644
index 0000000000..3f3800a1d5
--- /dev/null
+++ b/plugins/techdocs-backend/examples/documented-component/docs/deeper-nav/index.md
@@ -0,0 +1,11 @@
+# Deeper Nav
+
+Useful to test ExpandableNavigationAddon!
+
+## Some nav for TOC
+
+Yes!
+
+### Some deeper TOC nav
+
+## What? A second element with long text!?
diff --git a/plugins/techdocs-backend/examples/documented-component/mkdocs.yml b/plugins/techdocs-backend/examples/documented-component/mkdocs.yml
index fd954225a3..4632c6eb13 100644
--- a/plugins/techdocs-backend/examples/documented-component/mkdocs.yml
+++ b/plugins/techdocs-backend/examples/documented-component/mkdocs.yml
@@ -8,6 +8,10 @@ nav:
   - 'Code Sample': code/code-sample.md
   - Extensions: extensions.md
   - 'Inner Component Docs': inner-component-docs/index.md
+  - 'Deeper Nav':
+      - deeper-nav/index.md
+      - 'Inner Deeper Nav':
+          - 'Inner Inner Deeper Nav': deeper-nav/even-deeper/index.md
 
 plugins:
   - techdocs-core
diff --git a/plugins/techdocs-module-addons-contrib/src/ExpandableNavigation/ExpandableNavigation.tsx b/plugins/techdocs-module-addons-contrib/src/ExpandableNavigation/ExpandableNavigation.tsx
index 83e34f411a..2a18e642fa 100644
--- a/plugins/techdocs-module-addons-contrib/src/ExpandableNavigation/ExpandableNavigation.tsx
+++ b/plugins/techdocs-module-addons-contrib/src/ExpandableNavigation/ExpandableNavigation.tsx
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { useEffect, useCallback, useState } from 'react';
+import { useEffect, useState } from 'react';
 import { useLocalStorageValue } from '@react-hookz/web';
 import { Button, withStyles } from '@material-ui/core';
 import ChevronRightIcon from '@material-ui/icons/ChevronRight';
@@ -73,71 +73,33 @@ export const ExpandableNavigationAddon = () => {
     NESTED_LIST_TOGGLE,
   ]);
 
-  const shouldToggle = useCallback(
-    (item: HTMLInputElement) => {
-      const isExpanded = item.checked;
-      const shouldExpand = expanded?.expandAllNestedNavs;
-
-      // Is collapsed but should expand
-      if (shouldExpand && !isExpanded) {
-        return true;
-      }
-
-      // Is expanded but should collapse
-      if (!shouldExpand && isExpanded) {
-        return true;
-      }
-
-      return false;
-    },
-    [expanded],
-  );
-  const handleKeyPass = (
+  // Define handleKeyPass as a named function
+  function handleKeyPass(
     event: React.KeyboardEvent<HTMLElement>,
     toggleAction: () => void,
-  ) => {
+  ) {
     if (event.key === 'Enter' || event.key === ' ') {
       event.preventDefault();
       toggleAction();
     }
-  };
-  useEffect(() => {
-    // There is no nested navs
-    if (!checkboxToggles?.length) return;
+  }
 
+  useEffect(() => {
+    if (!checkboxToggles?.length) return;
     setHasNavSubLevels(true);
-    checkboxToggles.forEach(item => {
-      item.tabIndex = 0;
-      const toggleAction = () => {
-        if (shouldToggle(item)) {
-          item.click();
-        }
-      };
-      // Add keyboard event listener
-      const keydownHandler = (event: KeyboardEvent) => {
-        handleKeyPass(
-          event as unknown as React.KeyboardEvent<HTMLDivElement>,
-          toggleAction,
-        );
-      };
-      item.addEventListener('keydown', keydownHandler);
-      item.addEventListener('click', toggleAction);
+  }, [checkboxToggles]);
 
-      // Clean up event listener or unmount
-      return () => {
-        item.removeEventListener('keydown', keydownHandler);
-        item.removeEventListener('click', toggleAction);
-      };
-    });
-  }, [checkboxToggles, shouldToggle]);
   useEffect(() => {
     if (!checkboxToggles?.length) return;
-    checkboxToggles.forEach(item => {
+    function shouldToggle(item: HTMLInputElement) {
+      return expanded?.expandAllNestedNavs !== item.checked;
+    }
+    for (const item of checkboxToggles) {
       if (shouldToggle(item)) {
         item.click();
       }
-    });
-  }, [expanded, checkboxToggles, shouldToggle]);
+    }
+  }, [expanded, checkboxToggles]);
 
   const handleState = () => {
     setExpanded(prevState => ({
@@ -145,13 +107,17 @@ export const ExpandableNavigationAddon = () => {
     }));
   };
 
+  function handleButtonKeyDown(event: React.KeyboardEvent<HTMLElement>) {
+    handleKeyPass(event, handleState);
+  }
+
   return (
     <>
       {hasNavSubLevels ? (
         <StyledButton
           size="small"
           onClick={handleState}
-          onKeyDown={event => handleKeyPass(event, handleState)}
+          onKeyDown={handleButtonKeyDown}
           tabIndex={0} // Ensuring keyboard focus
           aria-expanded={expanded?.expandAllNestedNavs} // Accessibility
           aria-label={