Make isScrolling a function for performance

Author: Ives van Hoorne

packages/app/src/app/pages/Dashboard/Content/SandboxCard/index.js

@@ -103,7 +103,7 @@ class SandboxItem extends React.PureComponent<Props> {
       if (
         this.el &&
         typeof this.el.focus === 'function' &&
-        !this.props.isScrolling
+        !this.props.isScrolling()
       ) {
         this.el.focus();
       }

packages/app/src/app/pages/Dashboard/Content/SandboxGrid/index.js

@@ -192,8 +192,11 @@ class SandboxGrid extends React.Component<*, State> {
       });
     }
   };
+  isScrolling = () => this.scrolling;
 
   cellRenderer = ({ rowIndex, columnIndex, key, style, isScrolling }) => {
+    this.scrolling = isScrolling;
+
     let index = rowIndex * this.columnCount + columnIndex;
     const { sandboxes, signals } = this.props;
 
@@ -238,7 +241,7 @@ class SandboxGrid extends React.Component<*, State> {
 
     return (
       <SandboxItem
-        isScrolling={isScrolling}
+        isScrolling={this.isScrolling}
         id={item.id}
         title={item.title || item.id}
         details={editedSince}