addressed comments

src/lib/core/a11y/focus-trap.ts

@@ -1,12 +1,4 @@
-import {
-    Component,
-    ViewEncapsulation,
-    ViewChild,
-    ElementRef,
-    Input,
-    AfterContentInit,
-    NgZone
-} from '@angular/core';
+import {Component, ViewEncapsulation, ViewChild, ElementRef, Input, NgZone} from '@angular/core';
 import {InteractivityChecker} from './interactivity-checker';
 import {coerceBooleanProperty} from '../coersion/boolean-property';
 
@@ -29,29 +21,17 @@ import {coerceBooleanProperty} from '../coersion/boolean-property';
   <div *ngIf="active" tabindex="0" (focus)="focusFirstTabbableElement()"></div>`,
   encapsulation: ViewEncapsulation.None,
 })
-export class FocusTrap implements AfterContentInit {
+export class FocusTrap {
   @ViewChild('trappedContent') trappedContent: ElementRef;
 
-  @Input()
-  get active(): boolean { return this._active; }
-  set active(val: boolean) { this._active = coerceBooleanProperty(val); }
-
-  /** Whether the DOM content is ready. */
-  private _contentReady: boolean = false;
-
   /** Whether the focus trap is active. */
-  private _active: boolean = true;
+  @Input()
+  get disabled(): boolean { return this._disabled; }
+  set disabled(val: boolean) { this._disabled = coerceBooleanProperty(val); }
+  private _disabled: boolean = false;
 
   constructor(private _checker: InteractivityChecker, private _ngZone: NgZone) { }
 
-  ngAfterContentInit() {
-    this._contentReady = true;
-    // Trigger setter behavior.
-    if (this.active) {
-
-    }
-  }
-
   /**
    * Waits for microtask queue to empty, then focuses the first tabbable element within the focus
    * trap region.

src/lib/sidenav/sidenav.spec.ts

@@ -256,49 +256,49 @@ describe('MdSidenav', () => {
     let fixture: ComponentFixture<SidenavWitFocusableElements>;
     let testComponent: SidenavWitFocusableElements;
     let sidenav: MdSidenav;
-    let link1Element: HTMLElement;
-    let link2Element: HTMLElement;
+    let firstFocusableElement: HTMLElement;
+    let lastFocusableElement: HTMLElement;
 
     beforeEach(() => {
       fixture = TestBed.createComponent(SidenavWitFocusableElements);
       testComponent = fixture.debugElement.componentInstance;
       sidenav = fixture.debugElement.query(By.directive(MdSidenav)).componentInstance;
-      link1Element = fixture.debugElement.query(By.css('.link1')).nativeElement;
-      link2Element = fixture.debugElement.query(By.css('.link1')).nativeElement;
-      link2Element.focus();
+      firstFocusableElement = fixture.debugElement.query(By.css('.link1')).nativeElement;
+      lastFocusableElement = fixture.debugElement.query(By.css('.link1')).nativeElement;
+      lastFocusableElement.focus();
     });
 
-    it('should trp focus when opened in "over" mode', fakeAsync(() => {
+    it('should trap focus when opened in "over" mode', fakeAsync(() => {
       testComponent.mode = 'over';
-      link2Element.focus();
+      lastFocusableElement.focus();
 
       sidenav.open();
       endSidenavTransition(fixture);
       tick();
 
-      expect(document.activeElement).toBe(link1Element);
+      expect(document.activeElement).toBe(firstFocusableElement);
     }));
 
-    it('should trap tabs when opened in "push" mode', fakeAsync(() => {
+    it('should trap focus when opened in "push" mode', fakeAsync(() => {
       testComponent.mode = 'push';
-      link2Element.focus();
+      lastFocusableElement.focus();
 
       sidenav.open();
       endSidenavTransition(fixture);
       tick();
 
-      expect(document.activeElement).toBe(link1Element);
+      expect(document.activeElement).toBe(firstFocusableElement);
     }));
 
-    it('should not trap tabs when opened in "side" mode', fakeAsync(() => {
+    it('should not trap focus when opened in "side" mode', fakeAsync(() => {
       testComponent.mode = 'side';
-      link2Element.focus();
+      lastFocusableElement.focus();
 
       sidenav.open();
       endSidenavTransition(fixture);
       tick();
 
-      expect(document.activeElement).toBe(link2Element);
+      expect(document.activeElement).toBe(lastFocusableElement);
     }));
   });
 });

src/lib/sidenav/sidenav.ts

@@ -38,7 +38,7 @@ export class MdDuplicatedSidenavError extends MdError {
 @Component({
   moduleId: module.id,
   selector: 'md-sidenav',
-  template: '<focus-trap [active]="focusTrapActive"><ng-content></ng-content></focus-trap>',
+  template: '<focus-trap [disabled]="isFocusTrapDisabled"><ng-content></ng-content></focus-trap>',
   host: {
     '(transitionend)': '_onTransitionEnd($event)',
     // must prevent the browser from aligning text based on value
@@ -111,8 +111,9 @@ export class MdSidenav implements AfterContentInit {
   /** Event emitted when the sidenav alignment changes. */
   @Output('align-changed') onAlignChanged = new EventEmitter<void>();
 
-  get focusTrapActive() {
-    return this.opened && this.mode != 'side';
+  get isFocusTrapDisabled() {
+    // The focus trap is only enabled when the sidenav is open in any mode other than side.
+    return !this.opened || this.mode == 'side';
   }
 
   /**
@@ -181,7 +182,7 @@ export class MdSidenav implements AfterContentInit {
       this.onCloseStart.emit();
     }
 
-    if (this.focusTrapActive) {
+    if (!this.isFocusTrapDisabled) {
       this._focusTrap.focusFirstTabbableElementWhenReady();
     }