diff --git a/src/browser/services/DecorationService.ts b/src/browser/services/DecorationService.ts
index 8cbaaa32..cd32743b 100644
--- a/src/browser/services/DecorationService.ts
+++ b/src/browser/services/DecorationService.ts
@@ -11,7 +11,7 @@ import { IDecorationOptions, IDecoration, IMarker } from 'xterm';
 
 export class DecorationService extends Disposable implements IDecorationService {
 
-  private _decorations: Decoration[] = [];
+  private readonly _decorations: Decoration[] = [];
   private _screenElement: HTMLElement | undefined;
 
   constructor(
@@ -61,11 +61,10 @@ export class DecorationService extends Disposable implements IDecorationService
 }
 
 class Decoration extends Disposable implements IDecoration {
-  public readonly id: number = Decoration._nextId++;
-  private static _nextId: number = 1;
-
-  private _marker: IMarker;
+  private static _nextId = 1;
+  private readonly _marker: IMarker;
   private _element: HTMLElement | undefined;
+  private readonly _id: number = Decoration._nextId++;
   public isDisposed: boolean = false;
 
   public get element(): HTMLElement | undefined { return this._element; }
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index 0a307f31..17bf8d50 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -942,7 +942,7 @@ declare module 'xterm' {
      *  @param decorationOptions, which takes a marker and an optional anchor, 
      *  width, height, and x offset from the anchor. Returns the decoration or
      *  undefined if the alt buffer is active or the marker has already been disposed of.
-     *  @throws if the @param decorationOptions includes a negative x offset.
+     *  @throws when options include a negative x offset.
      */
     registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined;