adjust

src/client/js/components/ExpandOrContractButton.jsx

@@ -1,13 +1,9 @@
-import React, { useMemo } from 'react';
+import React from 'react';
 import PropTypes from 'prop-types';
 
 function ExpandOrContractButton(props) {
   const { isWindowExpanded, contractWindow, expandWindow } = props;
 
-  const getClassName = useMemo(() => {
-    return isWindowExpanded ? 'icon-size-actual' : 'icon-size-fullscreen';
-  }, [isWindowExpanded]);
-
   const clickContractButtonHandler = () => {
     if (contractWindow != null) {
       contractWindow();
@@ -22,7 +18,7 @@ function ExpandOrContractButton(props) {
 
   return (
     <button type="button" className="close" onClick={isWindowExpanded ? clickContractButtonHandler : clickExpandButtonHandler}>
-      <i className={getClassName} style={{ fontSize: '0.8em' }} aria-hidden="true"></i>
+      <i className={`${isWindowExpanded ? 'icon-size-actual' : 'icon-size-fullscreen'}`} style={{ fontSize: '0.8em' }} aria-hidden="true"></i>
     </button>
   );
 }