set fallback

src/common/services/DecorationService.ts

@@ -65,6 +65,9 @@ class Decoration extends Disposable implements IInternalDecoration {
   ) {
     super();
     this.marker = options.marker;
+    if (this.options.overviewRulerOptions && !this.options.overviewRulerOptions.position) {
+      this.options.overviewRulerOptions.position = 'full';
+    }
   }
   public override dispose(): void {
     this._onDispose.fire();

typings/xterm.d.ts

@@ -479,7 +479,7 @@ declare module 'xterm' {
      * @param color The color of the decoration.
      * @param position The position of the decoration.
      */
-    readonly overviewRulerOptions?: { color: string; position: 'left' | 'center' | 'right' | 'full'}
+    readonly overviewRulerOptions?: { color: string; position?: 'left' | 'center' | 'right' | 'full'}
   }
 
   /**