src/vs/workbench/contrib/search/browser/searchWidget.ts/SearchWidget/onToggleReplaceButton
class SearchWidget:	private onToggleReplaceButton(): void {
		this.replaceContainer.classList.toggle('disabled');
		if (this.isReplaceShown()) {
			this.toggleReplaceButton.element.classList.remove(...ThemeIcon.asClassNameArray(searchHideReplaceIcon));
			this.toggleReplaceButton.element.classList.add(...ThemeIcon.asClassNameArray(searchShowReplaceIcon));
		} else {
			this.toggleReplaceButton.element.classList.remove(...ThemeIcon.asClassNameArray(searchShowReplaceIcon));
			this.toggleReplaceButton.element.classList.add(...ThemeIcon.asClassNameArray(searchHideReplaceIcon));
		}
		this.toggleReplaceButton.element.setAttribute('aria-expanded', this.isReplaceShown() ? 'true' : 'false');
		this.updateReplaceActiveState();
		this._onReplaceToggled.fire();
	}