explorer: do not always recursvily refresh

src/vs/workbench/parts/files/electron-browser/views/explorerView.ts

@@ -350,15 +350,17 @@ export class ExplorerView extends ViewletPanel {
 
 	/**
 	 * Refresh the contents of the explorer to get up to date data from the disk about the file structure.
+	 * If the item is passed we refresh only that level of the tree, otherwise we do a full refresh.
 	 */
 	refresh(item?: ExplorerItem): Promise<void> {
 		if (!this.tree || !this.isBodyVisible()) {
 			this.shouldRefresh = true;
 			return Promise.resolve(undefined);
 		}
+		const recursive = !item;
 		const toRefresh = item || this.tree.getInput();
 
-		return this.tree.refresh(toRefresh, true);
+		return this.tree.refresh(toRefresh, recursive);
 	}
 
 	getOptimalWidth(): number {