src/vs/workbench/contrib/scm/browser/scmViewPane.ts/ViewModel/_onDidSpliceGroup
class ViewModel:	private _onDidSpliceGroup(item: IGroupItem, { start, deleteCount, toInsert }: ISplice<ISCMResource>): void {
		const before = item.resources.length;
		const deleted = item.resources.splice(start, deleteCount, ...toInsert);
		const after = item.resources.length;

		if (this._mode === ViewModelMode.Tree) {
			for (const resource of deleted) {
				item.tree.delete(resource.sourceUri);
			}

			for (const resource of toInsert) {
				item.tree.add(resource.sourceUri, resource);
			}
		}

		if (before !== after && (before === 0 || after === 0)) {
			this.refresh();
		} else {
			this.refresh(item);
		}
	}