diff --git a/src/Actions/Indent.ts b/src/Actions/Indent.ts
index ad254d24..efecabfa 100644
--- a/src/Actions/Indent.ts
+++ b/src/Actions/Indent.ts
@@ -1,6 +1,7 @@
 import {window, Range} from 'vscode';
 import {StaticReflect} from '../LanguageExtensions/StaticReflect';
 import {SymbolMetadata} from '../Symbols/Metadata';
+import {Configuration} from '../Configuration';
 import {RangeOffset} from '../Types/RangeOffset';
 import {ActionSelection} from './Selection';
 import {ActionMoveCursor} from './MoveCursor';
@@ -11,10 +12,8 @@ import {UtilText} from '../Utils/Text';
 export class ActionIndent {
 
     private static getIndentUnit(): string {
-        const options = window.activeTextEditor.options;
-
-        if (options.insertSpaces) {
-            return ' '.repeat(options.tabSize as number);
+        if (Configuration.getInsertSpace()) {
+            return ' '.repeat(Configuration.getTabSize() as number);
         }
         else {
             return '\t';
@@ -28,8 +27,7 @@ export class ActionIndent {
             return 0;
         }
 
-        const options = window.activeTextEditor.options;
-        const tabSize = options.tabSize as number;
+        const tabSize = Configuration.getTabSize();
 
         const line = document.lineAt(lineNumber);
 
diff --git a/src/Configuration.ts b/src/Configuration.ts
index f99e83d7..7122947d 100644
--- a/src/Configuration.ts
+++ b/src/Configuration.ts
@@ -1,4 +1,4 @@
-import {commands, workspace, WorkspaceConfiguration, Disposable} from 'vscode';
+import {commands, window, workspace, WorkspaceConfiguration, Disposable} from 'vscode';
 import {UtilWord} from './Utils/Word';
 
 export class Configuration {
@@ -46,6 +46,34 @@ export class Configuration {
         return this.editorNamespace.get(section, defaultValue);
     }
 
+    /**
+     * Remarks: Workaround undefined bug in native API.
+     */
+    static getInsertSpace(): boolean {
+        if (window.activeTextEditor) {
+            const options = window.activeTextEditor.options;
+            if (options.insertSpaces !== undefined) {
+                return options.insertSpaces as boolean;
+            }
+        }
+
+        return this.getEditorSetting<boolean>('insertSpaces');
+    }
+
+    /**
+     * Remarks: Workaround undefined bug in native API.
+     */
+    static getTabSize(): number {
+        if (window.activeTextEditor) {
+            const options = window.activeTextEditor.options;
+            if (options.tabSize !== undefined) {
+                return options.tabSize as number;
+            }
+        }
+
+        return this.getEditorSetting<number>('tabSize');
+    }
+
     static dispose(): void {
         Disposable.from(...this.disposables).dispose();
     }