diff --git a/spec/atom-environment-spec.coffee b/spec/atom-environment-spec.coffee
index 846083b0e..a78190ab7 100644
--- a/spec/atom-environment-spec.coffee
+++ b/spec/atom-environment-spec.coffee
@@ -208,12 +208,15 @@ describe "AtomEnvironment", ->
       waitsForPromise ->
         atom.loadState().then (state) -> expect(state).toEqual(serializedState)
 
-    it "saves state on keydown, mousedown, and when the editor window unloads", ->
+    it "saves state when the CPU is idle after a keydown or mousedown event", ->
       spyOn(atom, 'saveState')
+      idleCallbacks = []
+      spyOn(window, 'requestIdleCallback').andCallFake (callback) -> idleCallbacks.push(callback)
 
       keydown = new KeyboardEvent('keydown')
       atom.document.dispatchEvent(keydown)
       advanceClock atom.saveStateDebounceInterval
+      idleCallbacks.shift()()
       expect(atom.saveState).toHaveBeenCalledWith({isUnloading: false})
       expect(atom.saveState).not.toHaveBeenCalledWith({isUnloading: true})
 
@@ -221,17 +224,33 @@ describe "AtomEnvironment", ->
       mousedown = new MouseEvent('mousedown')
       atom.document.dispatchEvent(mousedown)
       advanceClock atom.saveStateDebounceInterval
+      idleCallbacks.shift()()
       expect(atom.saveState).toHaveBeenCalledWith({isUnloading: false})
       expect(atom.saveState).not.toHaveBeenCalledWith({isUnloading: true})
 
-      atom.saveState.reset()
+    it "saves state immediately when unloading the editor window, ignoring pending and successive mousedown/keydown events", ->
+      spyOn(atom, 'saveState')
+      idleCallbacks = []
+      spyOn(window, 'requestIdleCallback').andCallFake (callback) -> idleCallbacks.push(callback)
+
+      mousedown = new MouseEvent('mousedown')
+      atom.document.dispatchEvent(mousedown)
       atom.unloadEditorWindow()
-      mousedown = new MouseEvent('mousedown')
-      atom.document.dispatchEvent(mousedown)
-      advanceClock atom.saveStateDebounceInterval
       expect(atom.saveState).toHaveBeenCalledWith({isUnloading: true})
       expect(atom.saveState).not.toHaveBeenCalledWith({isUnloading: false})
 
+      atom.saveState.reset()
+      advanceClock atom.saveStateDebounceInterval
+      idleCallbacks.shift()()
+      expect(atom.saveState).not.toHaveBeenCalled()
+
+      atom.saveState.reset()
+      mousedown = new MouseEvent('mousedown')
+      atom.document.dispatchEvent(mousedown)
+      advanceClock atom.saveStateDebounceInterval
+      idleCallbacks.shift()()
+      expect(atom.saveState).not.toHaveBeenCalled()
+
     it "serializes the project state with all the options supplied in saveState", ->
       spyOn(atom.project, 'serialize').andReturn({foo: 42})
 
diff --git a/src/atom-environment.coffee b/src/atom-environment.coffee
index f50ae9d5b..da3e989f2 100644
--- a/src/atom-environment.coffee
+++ b/src/atom-environment.coffee
@@ -234,13 +234,14 @@ class AtomEnvironment extends Model
     checkPortableHomeWritable()
 
   attachSaveStateListeners: ->
-    saveState = => @saveState({isUnloading: false}) unless @unloaded
-    debouncedSaveState = _.debounce(saveState, @saveStateDebounceInterval)
-    @document.addEventListener('mousedown', debouncedSaveState, true)
-    @document.addEventListener('keydown', debouncedSaveState, true)
+    saveState = _.debounce((=>
+      window.requestIdleCallback => @saveState({isUnloading: false}) unless @unloaded
+    ), @saveStateDebounceInterval)
+    @document.addEventListener('mousedown', saveState, true)
+    @document.addEventListener('keydown', saveState, true)
     @disposables.add new Disposable =>
-      @document.removeEventListener('mousedown', debouncedSaveState, true)
-      @document.removeEventListener('keydown', debouncedSaveState, true)
+      @document.removeEventListener('mousedown', saveState, true)
+      @document.removeEventListener('keydown', saveState, true)
 
   setConfigSchema: ->
     @config.setSchema null, {type: 'object', properties: _.clone(require('./config-schema'))}
@@ -655,6 +656,7 @@ class AtomEnvironment extends Model
 
   # Call this method when establishing a real application window.
   startEditorWindow: ->
+    @unloaded = false
     @loadState().then (state) =>
       @windowDimensions = state?.windowDimensions
       @displayWindow().then =>
@@ -842,16 +844,15 @@ class AtomEnvironment extends Model
     return Promise.resolve() unless @enablePersistence
 
     new Promise (resolve, reject) =>
-      window.requestIdleCallback =>
-        return if not @project
+      return if not @project
 
-        state = @serialize(options)
-        savePromise =
-          if storageKey = @getStateKey(@project?.getPaths())
-            @stateStore.save(storageKey, state)
-          else
-            @applicationDelegate.setTemporaryWindowState(state)
-        savePromise.catch(reject).then(resolve)
+      state = @serialize(options)
+      savePromise =
+        if storageKey = @getStateKey(@project?.getPaths())
+          @stateStore.save(storageKey, state)
+        else
+          @applicationDelegate.setTemporaryWindowState(state)
+      savePromise.catch(reject).then(resolve)
 
   loadState: ->
     if @enablePersistence