message: React: Improve performance by not rendering collapsed panels
diff: @@ -33,12 +33,15 @@ export class SurveyPanel extends SurveyPanelBase {
  creator={this.creator}
  />
  );
  -
  - var rows = this.renderRows();
  var style = {
  paddingLeft: this.panel.innerPaddingLeft,
  display: !this.panel.isCollapsed ? "block" : "none"
  };
  + var content = null;
  + if (!this.panel.isCollapsed) {
  + var rows = this.renderRows();
  + content = this.renderContent(style, rows);
  + }
  var rootStyle: { [index: string]: any } = {};
  if (this.panel.renderWidth) rootStyle["width"] = this.panel.renderWidth;
  var bottom = this.renderBottom();
  @@ -47,7 +50,7 @@ export class SurveyPanel extends SurveyPanelBase {
  {title}
  {description}
  {errors}
  - {this.renderContent(style, rows)}
  + {content}
  {bottom}
  </div>
  );
  