diff --git a/src/js/editor/editor.ts b/src/js/editor/editor.ts
index 793a7f530..822c3a389 100644
--- a/src/js/editor/editor.ts
+++ b/src/js/editor/editor.ts
@@ -1105,7 +1105,7 @@ export default class Editor implements EditorOptions {
    * @return {Boolean}
    */
   _hasFocus(): boolean {
-    return document.activeElement === this.element
+    return this.root.activeElement === this.element
   }
 
   /**
@@ -1347,4 +1347,18 @@ export default class Editor implements EditorOptions {
       }
     }
   }
+
+  get root() {
+    const root = this.element.getRootNode();
+
+    // COMPAT: Only Chrome implements the DocumentOrShadowRoot mixin for
+    // ShadowRoot; other browsers still implement it on the Document
+    // interface. (2020/08/08)
+    // https://developer.mozilla.org/en-US/docs/Web/API/ShadowRoot#Properties
+    if (root.getSelection === undefined && this.element.ownerDocument !== null) {
+      return this.element.ownerDocument
+    }
+
+    return root
+  }
 }
diff --git a/src/js/editor/selection-change-observer.ts b/src/js/editor/selection-change-observer.ts
index c5f6b0c52..99f470168 100644
--- a/src/js/editor/selection-change-observer.ts
+++ b/src/js/editor/selection-change-observer.ts
@@ -11,21 +11,22 @@ class SelectionChangeObserver {
   listeners: SelectionChangeListener[]
   selection: PartialSelection
 
-  constructor() {
+  constructor({ editor }) {
     this.started = false
     this.listeners = []
     this.selection = {} as PartialSelection
+    this.editor = editor
   }
 
-  static getInstance() {
+  static getInstance({ editor }) {
     if (!instance) {
-      instance = new SelectionChangeObserver()
+      instance = new SelectionChangeObserver({ editor })
     }
     return instance
   }
 
   static addListener(listener: SelectionChangeListener) {
-    SelectionChangeObserver.getInstance().addListener(listener)
+    SelectionChangeObserver.getInstance({ editor: listener.editor }).addListener(listener)
   }
 
   addListener(listener: SelectionChangeListener) {
@@ -74,8 +75,8 @@ class SelectionChangeObserver {
     this.listeners = []
   }
 
-  getSelection(): PartialSelection {
-    let selection = window.getSelection()!
+  getSelection(root = window): PartialSelection {
+    let selection = root.getSelection()!
     let { anchorNode, focusNode, anchorOffset, focusOffset } = selection
     return { anchorNode, focusNode, anchorOffset, focusOffset }
   }
@@ -93,7 +94,7 @@ class SelectionChangeObserver {
 
   update() {
     let prevSelection = this.selection
-    let curSelection = this.getSelection()!
+    let curSelection = this.getSelection(this.editor.root)!
     if (!this.selectionIsEqual(prevSelection, curSelection)) {
       this.selection = curSelection
       this.notifyListeners(curSelection, prevSelection)
diff --git a/src/js/utils/cursor.ts b/src/js/utils/cursor.ts
index dd8f5def1..0c0b9ccd8 100644
--- a/src/js/utils/cursor.ts
+++ b/src/js/utils/cursor.ts
@@ -11,6 +11,7 @@ import { unwrap, assertNotNull, expect } from './assert'
 import { isCardSection } from '../models/card'
 import Section from '../models/_section'
 import { Type } from '../models/types'
+import Browser from './browser';
 
 export { Position, Range }
 
@@ -26,7 +27,7 @@ class Cursor {
   }
 
   clearSelection() {
-    clearSelection()
+    clearSelection(this.editor.root)
   }
 
   /**
@@ -138,7 +139,7 @@ class Cursor {
   }
 
   get selection() {
-    return expect(window.getSelection(), 'expected window selection to not be null')
+    return expect(this.editor.root.getSelection(), 'expected editor.root selection to not be null')
   }
 
   selectedText() {
@@ -175,7 +176,28 @@ class Cursor {
   _hasSelection() {
     const element = unwrap(this.editor.element)
     const { _selectionRange } = this
-    if (!_selectionRange || _selectionRange.collapsed) {
+
+    // COMPAT: There's a bug in chrome that always returns `true` for
+    // `isCollapsed` for a Selection that comes from a ShadowRoot.
+    // (2020/08/08)
+    // https://bugs.chromium.org/p/chromium/issues/detail?id=447523
+    let isCollapsed;
+    const hasShadowRoot = () => {
+      return !!(
+        window.document.activeElement && window.document.activeElement.shadowRoot
+      )
+    }
+    if (_selectionRange) {
+      if (Browser.isChrome() && hasShadowRoot()) {
+        isCollapsed =
+          _selectionRange.anchorNode === _selectionRange.focusNode &&
+          _selectionRange.anchorOffset === _selectionRange.focusOffset
+      } else {
+        isCollapsed = _selectionRange.isCollapsed
+      }
+    }
+
+    if (!_selectionRange || isCollapsed) {
       return false
     }
 
diff --git a/src/js/utils/selection-utils.ts b/src/js/utils/selection-utils.ts
index 9dc338e8c..8844f4f4f 100644
--- a/src/js/utils/selection-utils.ts
+++ b/src/js/utils/selection-utils.ts
@@ -2,8 +2,8 @@ import { Direction } from './key'
 import { isTextNode, isElementNode } from './dom-utils'
 import { assertNotNull } from './assert'
 
-export function clearSelection() {
-  const selection = window.getSelection()
+export function clearSelection(root = window) {
+  const selection = root.getSelection()
   selection && selection.removeAllRanges()
 }