src/vs/workbench/browser/parts/views/treeView.ts/TreeView/updateContentAreas
class TreeView:	private updateContentAreas(): void {
		const isTreeEmpty = !this.root.children || this.root.children.length === 0;
		// Hide tree container only when there is a message and tree is empty and not refreshing
		if (this._messageValue && isTreeEmpty && !this.refreshing) {
			this.treeContainer.classList.add('hide');
			this.domNode.setAttribute('tabindex', '0');
		} else {
			this.treeContainer.classList.remove('hide');
			this.domNode.removeAttribute('tabindex');
		}
	}