When clicking on a changed submodule in the git window, do nothing.

extensions/git/src/commands.ts

@@ -13,6 +13,7 @@ import { toGitUri, fromGitUri } from './uri';
 import { grep } from './util';
 import { applyLineChanges, intersectDiffWithRange, toLineRanges, invertLineChange } from './staging';
 import * as path from 'path';
+import { lstatSync } from 'fs';
 import * as os from 'os';
 import TelemetryReporter from 'vscode-extension-telemetry';
 import * as nls from 'vscode-nls';
@@ -159,6 +160,9 @@ export class CommandCenter {
 	}
 
 	private async _openResource(resource: Resource, preview?: boolean, preserveFocus?: boolean, preserveSelection?: boolean): Promise<void> {
+		if (lstatSync(resource.resourceUri.fsPath).isDirectory()) {
+			return; // it's a submodule.
+		}
 		const left = this.getLeftResource(resource);
 		const right = this.getRightResource(resource);
 		const title = this.getTitle(resource);