diff --git a/src/tsconfig.strictNullChecks.json b/src/tsconfig.strictNullChecks.json
index 32daaec6794..6ff1e344469 100644
--- a/src/tsconfig.strictNullChecks.json
+++ b/src/tsconfig.strictNullChecks.json
@@ -9,6 +9,7 @@
 	],
 	"files": [
 		"./vs/base/browser/browser.ts",
+		"./vs/base/browser/dnd.ts",
 		"./vs/base/browser/dom.ts",
 		"./vs/base/browser/event.ts",
 		"./vs/base/browser/fastDomNode.ts",
@@ -362,6 +363,7 @@
 		"./vs/platform/editor/common/editor.ts",
 		"./vs/platform/environment/common/environment.ts",
 		"./vs/platform/extensionManagement/common/extensionManagement.ts",
+		"./vs/platform/extensionManagement/common/extensionNls.ts",
 		"./vs/platform/extensions/common/extensionHost.ts",
 		"./vs/platform/extensions/common/extensions.ts",
 		"./vs/platform/extensions/node/extensionValidator.ts",
@@ -374,6 +376,7 @@
 		"./vs/platform/instantiation/common/serviceCollection.ts",
 		"./vs/platform/integrity/common/integrity.ts",
 		"./vs/platform/integrity/node/integrityServiceImpl.ts",
+		"./vs/platform/issue/common/issue.ts",
 		"./vs/platform/jsonschemas/common/jsonContributionRegistry.ts",
 		"./vs/platform/keybinding/common/abstractKeybindingService.ts",
 		"./vs/platform/keybinding/common/keybinding.ts",
@@ -438,6 +441,7 @@
 		"./vs/workbench/parts/comments/electron-browser/commentGlyphWidget.ts",
 		"./vs/workbench/parts/execution/common/execution.ts",
 		"./vs/workbench/parts/extensions/common/extensionQuery.ts",
+		"./vs/workbench/parts/extensions/common/extensionsFileTemplate.ts",
 		"./vs/workbench/parts/logs/common/logConstants.ts",
 		"./vs/workbench/parts/markers/electron-browser/constants.ts",
 		"./vs/workbench/parts/markers/electron-browser/markers.ts",
@@ -452,6 +456,7 @@
 		"./vs/workbench/parts/terminal/browser/terminalWidgetManager.ts",
 		"./vs/workbench/parts/terminal/common/terminal.ts",
 		"./vs/workbench/parts/terminal/common/terminalCommands.ts",
+		"./vs/workbench/parts/terminal/common/terminalMenu.ts",
 		"./vs/workbench/parts/terminal/node/terminalCommandTracker.ts",
 		"./vs/workbench/parts/terminal/node/terminalEnvironment.ts",
 		"./vs/workbench/parts/webview/electron-browser/webviewProtocols.ts",
@@ -459,12 +464,14 @@
 		"./vs/workbench/parts/welcome/page/electron-browser/vs_code_welcome_page.ts",
 		"./vs/workbench/services/activity/common/activity.ts",
 		"./vs/workbench/services/backup/common/backup.ts",
+		"./vs/workbench/services/commands/common/commandService.ts",
 		"./vs/workbench/services/configuration/common/configuration.ts",
 		"./vs/workbench/services/configuration/common/jsonEditing.ts",
 		"./vs/workbench/services/configurationResolver/common/configurationResolver.ts",
 		"./vs/workbench/services/decorations/browser/decorations.ts",
 		"./vs/workbench/services/extensions/common/extensions.ts",
 		"./vs/workbench/services/extensions/common/extensionsRegistry.ts",
+		"./vs/workbench/services/extensions/node/extensionManagementServerService.ts",
 		"./vs/workbench/services/extensions/node/lazyPromise.ts",
 		"./vs/workbench/services/extensions/node/proxyIdentifier.ts",
 		"./vs/workbench/services/files/node/watcher/common.ts",
@@ -472,6 +479,7 @@
 		"./vs/workbench/services/files/node/watcher/unix/watcher.ts",
 		"./vs/workbench/services/hash/common/hashService.ts",
 		"./vs/workbench/services/hash/node/hashService.ts",
+		"./vs/workbench/services/jsonschemas/common/jsonValidationExtensionPoint.ts",
 		"./vs/workbench/services/keybinding/common/keybindingIO.ts",
 		"./vs/workbench/services/keybinding/common/keyboardMapper.ts",
 		"./vs/workbench/services/keybinding/common/macLinuxFallbackKeyboardMapper.ts",
@@ -482,8 +490,11 @@
 		"./vs/workbench/services/scm/common/scm.ts",
 		"./vs/workbench/services/scm/common/scmService.ts",
 		"./vs/workbench/services/search/node/search.ts",
+		"./vs/workbench/services/textMate/electron-browser/TMGrammars.ts",
 		"./vs/workbench/services/textMate/electron-browser/TMHelper.ts",
 		"./vs/workbench/services/textMate/electron-browser/textMateService.ts",
+		"./vs/workbench/services/textfile/electron-browser/textResourcePropertiesService.ts",
+		"./vs/workbench/services/themes/common/colorExtensionPoint.ts",
 		"./vs/workbench/services/themes/common/colorThemeSchema.ts",
 		"./vs/workbench/services/themes/common/fileIconThemeSchema.ts",
 		"./vs/workbench/services/themes/common/workbenchThemeService.ts",
diff --git a/src/vs/base/browser/dnd.ts b/src/vs/base/browser/dnd.ts
index 768765424c7..cc72a3d90c0 100644
--- a/src/vs/base/browser/dnd.ts
+++ b/src/vs/base/browser/dnd.ts
@@ -76,9 +76,11 @@ export function applyDragImage(event: DragEvent, label: string, clazz: string):
 	dragImage.className = clazz;
 	dragImage.textContent = label;
 
-	document.body.appendChild(dragImage);
-	event.dataTransfer.setDragImage(dragImage, -10, -10);
+	if (event.dataTransfer) {
+		document.body.appendChild(dragImage);
+		event.dataTransfer.setDragImage(dragImage, -10, -10);
 
-	// Removes the element when the DND operation is done
-	setTimeout(() => document.body.removeChild(dragImage), 0);
+		// Removes the element when the DND operation is done
+		setTimeout(() => document.body.removeChild(dragImage), 0);
+	}
 }
\ No newline at end of file