src/vs/base/browser/ui/tree/abstractTree.ts/FindController/render
class FindController:	private render(): void {
		const noMatches = this.filter.totalCount > 0 && this.filter.matchCount === 0;

		if (this.pattern && noMatches) {
			if (this.tree.options.showNotFoundMessage ?? true) {
				this.widget?.showMessage({ type: MessageType.WARNING, content: localize('not found', "No elements found.") });
			} else {
				this.widget?.showMessage({ type: MessageType.WARNING });
			}
		} else {
			this.widget?.clearMessage();
		}
	}