diff --git a/exports/atom.coffee b/exports/atom.coffee
index fd2e175e2..35a65c566 100644
--- a/exports/atom.coffee
+++ b/exports/atom.coffee
@@ -1,4 +1,4 @@
-{Document, Point, Range} = require 'telepath'
+{Document, Model, Point, Range} = require 'telepath'
 
 module.exports =
   _: require 'underscore-plus'
@@ -9,6 +9,7 @@ module.exports =
   File: require '../src/file'
   fs: require 'fs-plus'
   Git: require '../src/git'
+  Model: Model
   Point: Point
   Range: Range
 
diff --git a/package.json b/package.json
index a4a860c37..36af98666 100644
--- a/package.json
+++ b/package.json
@@ -23,6 +23,7 @@
     "clear-cut": "0.2.0",
     "coffee-script": "1.6.3",
     "coffeestack": "0.6.0",
+    "diff": "git://github.com/benogle/jsdiff.git",
     "emissary": "0.19.0",
     "first-mate": "0.5.0",
     "fs-plus": "0.11.0",
@@ -42,7 +43,7 @@
     "scandal": "0.8.0",
     "season": "0.14.0",
     "semver": "1.1.4",
-    "space-pen": "2.0.1",
+    "space-pen": "2.0.2",
     "telepath": "0.73.0",
     "temp": "0.5.0",
     "underscore-plus": "0.5.0"
@@ -73,12 +74,13 @@
     "github-releases": "~0.2.0"
   },
   "packageDependencies": {
-    "atom-dark-syntax": "0.8.0",
+    "atom-dark-syntax": "0.10.0",
     "atom-dark-ui": "0.17.0",
-    "atom-light-syntax": "0.9.0",
+    "atom-light-syntax": "0.10.0",
     "atom-light-ui": "0.16.0",
-    "base16-tomorrow-dark-theme": "0.7.0",
-    "solarized-dark-syntax": "0.5.0",
+    "base16-tomorrow-dark-theme": "0.8.0",
+    "solarized-dark-syntax": "0.6.0",
+    "solarized-light-syntax": "0.2.0",
     "archive-view": "0.16.0",
     "autocomplete": "0.18.0",
     "autoflow": "0.11.0",
@@ -87,14 +89,14 @@
     "bracket-matcher": "0.15.0",
     "command-logger": "0.8.0",
     "command-palette": "0.13.0",
-    "dev-live-reload": "0.18.0",
-    "editor-stats": "0.8.0",
-    "exception-reporting": "0.8.0",
+    "dev-live-reload": "0.20.0",
+    "editor-stats": "0.9.0",
+    "exception-reporting": "0.9.0",
     "feedback": "0.16.0",
-    "find-and-replace": "0.58.0",
+    "find-and-replace": "0.59.0",
     "fuzzy-finder": "0.28.0",
     "gists": "0.13.0",
-    "git-diff": "0.20.0",
+    "git-diff": "0.21.0",
     "github-sign-in": "0.15.0",
     "go-to-line": "0.12.0",
     "grammar-selector": "0.13.0",
@@ -115,7 +117,7 @@
     "terminal": "0.23.0",
     "timecop": "0.11.0",
     "to-the-hubs": "0.15.0",
-    "tree-view": "0.44.0",
+    "tree-view": "0.48.0",
     "visual-bell": "0.6.0",
     "welcome": "0.3.0",
     "whitespace": "0.10.0",
diff --git a/spec/editor-spec.coffee b/spec/editor-spec.coffee
index b99be281b..cb7a75674 100644
--- a/spec/editor-spec.coffee
+++ b/spec/editor-spec.coffee
@@ -2624,6 +2624,7 @@ describe "Editor", ->
 
     describe ".shouldPromptToSave()", ->
       it "returns false when an edit session's buffer is in use by more than one session", ->
+        jasmine.unspy(editor, 'shouldPromptToSave')
         expect(editor.shouldPromptToSave()).toBeFalsy()
         buffer.setText('changed')
         expect(editor.shouldPromptToSave()).toBeTruthy()
diff --git a/spec/pane-spec.coffee b/spec/pane-spec.coffee
index 75d3661dc..d47d0687b 100644
--- a/spec/pane-spec.coffee
+++ b/spec/pane-spec.coffee
@@ -1,6 +1,6 @@
 PaneContainer = require '../src/pane-container'
 Pane = require '../src/pane'
-{$, View} = require 'atom'
+{fs, $, View} = require 'atom'
 path = require 'path'
 temp = require 'temp'
 
@@ -147,6 +147,7 @@ describe "Pane", ->
 
     describe "if the item is modified", ->
       beforeEach ->
+        jasmine.unspy(editor2, 'shouldPromptToSave')
         spyOn(editor2, 'save')
         spyOn(editor2, 'saveAs')
 
@@ -347,14 +348,14 @@ describe "Pane", ->
 
       describe "when the current item has a saveAs method", ->
         it "opens a save dialog and saves the current item as the selected path", ->
-          spyOn(editor2, 'saveAs')
-          editor2.buffer.setPath(undefined)
-          pane.showItem(editor2)
+          newEditor = atom.project.openSync()
+          spyOn(newEditor, 'saveAs')
+          pane.showItem(newEditor)
 
           pane.trigger 'core:save'
 
           expect(atom.showSaveDialogSync).toHaveBeenCalled()
-          expect(editor2.saveAs).toHaveBeenCalledWith('/selected/path')
+          expect(newEditor.saveAs).toHaveBeenCalledWith('/selected/path')
 
       describe "when the current item has no saveAs method", ->
         it "does nothing", ->
@@ -421,6 +422,17 @@ describe "Pane", ->
       view2.trigger 'title-changed'
       expect(activeItemTitleChangedHandler).toHaveBeenCalled()
 
+  describe "when an unmodifed buffer's path is deleted", ->
+    it "removes the pane item", ->
+      filePath = temp.openSync('atom').path
+      editor = atom.project.openSync(filePath)
+      pane.showItem(editor)
+      expect(pane.items).toHaveLength(5)
+
+      fs.removeSync(filePath)
+      waitsFor ->
+        pane.items.length == 4
+
   describe ".remove()", ->
     it "destroys all the pane's items", ->
       pane.remove()
diff --git a/spec/spec-helper.coffee b/spec/spec-helper.coffee
index 629c99890..1bd3b9e1c 100644
--- a/spec/spec-helper.coffee
+++ b/spec/spec-helper.coffee
@@ -9,6 +9,7 @@ Keymap = require '../src/keymap'
 Config = require '../src/config'
 {Point} = require 'telepath'
 Project = require '../src/project'
+Editor = require '../src/editor'
 EditorView = require '../src/editor-view'
 TokenizedBuffer = require '../src/tokenized-buffer'
 pathwatcher = require 'pathwatcher'
@@ -91,6 +92,7 @@ beforeEach ->
   spyOn(window, "setTimeout").andCallFake window.fakeSetTimeout
   spyOn(window, "clearTimeout").andCallFake window.fakeClearTimeout
   spyOn(File.prototype, "detectResurrectionAfterDelay").andCallFake -> @detectResurrection()
+  spyOn(Editor.prototype, "shouldPromptToSave").andReturn false
 
   # make tokenization synchronous
   TokenizedBuffer.prototype.chunkSize = Infinity
diff --git a/spec/text-buffer-spec.coffee b/spec/text-buffer-spec.coffee
index 31066cd5b..6bc53aff5 100644
--- a/spec/text-buffer-spec.coffee
+++ b/spec/text-buffer-spec.coffee
@@ -34,11 +34,11 @@ describe 'TextBuffer', ->
           expect(buffer.getText()).toBe fs.readFileSync(filePath, 'utf8')
 
       describe "when no file exists for the path", ->
-        it "is modified and is initially empty", ->
+        it "is not modified and is initially empty", ->
           filePath = "does-not-exist.txt"
           expect(fs.existsSync(filePath)).toBeFalsy()
           buffer = atom.project.bufferForPathSync(filePath)
-          expect(buffer.isModified()).toBeTruthy()
+          expect(buffer.isModified()).not.toBeTruthy()
           expect(buffer.getText()).toBe ''
 
     describe "when no path is given", ->
@@ -113,10 +113,17 @@ describe 'TextBuffer', ->
 
         runs ->
           [event] = changeHandler.argsForCall[0]
-          expect(event.oldRange).toEqual [[0, 0], [0, 5]]
+          expect(event.oldRange).toEqual [[0, 0], [0, 0]]
           expect(event.newRange).toEqual [[0, 0], [0, 6]]
-          expect(event.oldText).toBe "first"
+          expect(event.oldText).toBe ""
           expect(event.newText).toBe "second"
+
+          [event] = changeHandler.argsForCall[1]
+          expect(event.oldRange).toEqual [[0, 6], [0, 11]]
+          expect(event.newRange).toEqual [[0, 6], [0, 6]]
+          expect(event.oldText).toBe "first"
+          expect(event.newText).toBe ""
+
           expect(buffer.isModified()).toBeFalsy()
 
     describe "when the buffer's memory contents differ from the *previous* disk contents", ->
@@ -160,20 +167,38 @@ describe 'TextBuffer', ->
       filePath = bufferToDelete.getPath() # symlinks may have been converted
 
       expect(bufferToDelete.getPath()).toBe filePath
-      expect(bufferToDelete.isModified()).toBeFalsy()
-
-      removeHandler = jasmine.createSpy('removeHandler')
-      bufferToDelete.file.on 'removed', removeHandler
-      fs.removeSync(filePath)
-      waitsFor "file to be removed", ->
-        removeHandler.callCount > 0
 
     afterEach ->
       bufferToDelete.destroy()
 
-    it "retains its path and reports the buffer as modified", ->
-      expect(bufferToDelete.getPath()).toBe filePath
-      expect(bufferToDelete.isModified()).toBeTruthy()
+    describe "when the file is modified", ->
+      beforeEach ->
+        bufferToDelete.setText("I WAS MODIFIED")
+        expect(bufferToDelete.isModified()).toBeTruthy()
+
+        removeHandler = jasmine.createSpy('removeHandler')
+        bufferToDelete.file.on 'removed', removeHandler
+        fs.removeSync(filePath)
+        waitsFor "file to be removed", ->
+          removeHandler.callCount > 0
+
+      it "retains its path and reports the buffer as modified", ->
+        expect(bufferToDelete.getPath()).toBe filePath
+        expect(bufferToDelete.isModified()).toBeTruthy()
+
+    describe "when the file is not modified", ->
+      beforeEach ->
+        expect(bufferToDelete.isModified()).toBeFalsy()
+
+        removeHandler = jasmine.createSpy('removeHandler')
+        bufferToDelete.file.on 'removed', removeHandler
+        fs.removeSync(filePath)
+        waitsFor "file to be removed", ->
+          removeHandler.callCount > 0
+
+      it "retains its path and reports the buffer as not modified", ->
+        expect(bufferToDelete.getPath()).toBe filePath
+        expect(bufferToDelete.isModified()).toBeFalsy()
 
     it "resumes watching of the file when it is re-saved", ->
       bufferToDelete.save()
@@ -210,19 +235,6 @@ describe 'TextBuffer', ->
       advanceClock(buffer.stoppedChangingDelay)
       expect(modifiedHandler).toHaveBeenCalledWith(false)
 
-    it "reports the modified status changing to true after the underlying file is deleted", ->
-      buffer.release()
-      filePath = path.join(temp.dir, 'atom-tmp-file')
-      fs.writeFileSync(filePath, 'delete me')
-      buffer = atom.project.bufferForPathSync(filePath)
-      modifiedHandler = jasmine.createSpy("modifiedHandler")
-      buffer.on 'modified-status-changed', modifiedHandler
-
-      fs.removeSync(filePath)
-
-      waitsFor "modified status to change", -> modifiedHandler.callCount
-      runs -> expect(buffer.isModified()).toBe true
-
     it "reports the modified status changing to false after a modified buffer is saved", ->
       filePath = path.join(temp.dir, 'atom-tmp-file')
       fs.writeFileSync(filePath, '')
@@ -454,6 +466,68 @@ describe 'TextBuffer', ->
       expect(event.oldRange).toEqual expectedPreRange
       expect(event.newRange).toEqual [[0, 0], [1, 14]]
 
+  describe ".setTextViaDiff(text)", ->
+    it "can change the entire contents of the buffer when there are no newlines", ->
+      buffer.setText('BUFFER CHANGE')
+      newText = 'DISK CHANGE'
+      buffer.setTextViaDiff(newText)
+      expect(buffer.getText()).toBe newText
+
+    describe "with standard newlines", ->
+      it "can change the entire contents of the buffer with no newline at the end", ->
+        newText = "I know you are.\nBut what am I?"
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "can change the entire contents of the buffer with a newline at the end", ->
+        newText = "I know you are.\nBut what am I?\n"
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "can change a few lines at the beginning in the buffer", ->
+        newText = buffer.getText().replace(/function/g, 'omgwow')
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "can change a few lines in the middle of the buffer", ->
+        newText = buffer.getText().replace(/shift/g, 'omgwow')
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "can adds a newline at the end", ->
+        newText = buffer.getText() + '\n'
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+    describe "with windows newlines", ->
+      beforeEach ->
+        buffer.setText(buffer.getText().replace(/\n/g, '\r\n'))
+
+      it "adds a newline at the end", ->
+        newText = buffer.getText() + '\r\n'
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "changes the entire contents of the buffer with smaller content with no newline at the end", ->
+        newText = "I know you are.\r\nBut what am I?"
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "changes the entire contents of the buffer with smaller content with newline at the end", ->
+        newText = "I know you are.\r\nBut what am I?\r\n"
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "changes a few lines at the beginning in the buffer", ->
+        newText = buffer.getText().replace(/function/g, 'omgwow')
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
+      it "changes a few lines in the middle of the buffer", ->
+        newText = buffer.getText().replace(/shift/g, 'omgwow')
+        buffer.setTextViaDiff(newText)
+        expect(buffer.getText()).toBe newText
+
   describe ".save()", ->
     saveBuffer = null
 
diff --git a/spec/window-spec.coffee b/spec/window-spec.coffee
index 8d0d68fce..2b6f1a6fb 100644
--- a/spec/window-spec.coffee
+++ b/spec/window-spec.coffee
@@ -1,5 +1,6 @@
 {$, $$, fs} = require 'atom'
 path = require 'path'
+Editor = require '../src/editor'
 WindowEventHandler = require '../src/window-event-handler'
 
 describe "Window", ->
@@ -54,6 +55,7 @@ describe "Window", ->
     [beforeUnloadEvent] = []
 
     beforeEach ->
+      jasmine.unspy(Editor.prototype, "shouldPromptToSave")
       beforeUnloadEvent = $.Event(new Event('beforeunload'))
 
     describe "when pane items are are modified", ->
diff --git a/src/atom.coffee b/src/atom.coffee
index 538dea1bd..3c99098a6 100644
--- a/src/atom.coffee
+++ b/src/atom.coffee
@@ -191,7 +191,7 @@ class Atom extends Model
     @menu.update()
 
     $(window).on 'unload', =>
-      $(document.body).hide()
+      $(document.body).css('visibility', 'hidden')
       @unloadEditorWindow()
       false
 
diff --git a/src/editor-view.coffee b/src/editor-view.coffee
index fb1540d61..67a5d3ce7 100644
--- a/src/editor-view.coffee
+++ b/src/editor-view.coffee
@@ -780,6 +780,14 @@ class EditorView extends View
 
   afterAttach: (onDom) ->
     return unless onDom
+
+    # TODO: Remove this guard when we understand why this is happening
+    unless @editor.isAlive()
+      if atom.isReleasedVersion()
+        return
+      else
+        throw new Error("Assertion failure: EditorView is getting attached to a dead editor. Why?")
+
     @redraw() if @redrawOnReattach
     return if @attached
     @attached = true
diff --git a/src/editor.coffee b/src/editor.coffee
index cba3382fd..c033b4745 100644
--- a/src/editor.coffee
+++ b/src/editor.coffee
@@ -110,6 +110,7 @@ class Editor extends Model
     @subscribe @buffer, "contents-modified", => @emit "contents-modified"
     @subscribe @buffer, "contents-conflicted", => @emit "contents-conflicted"
     @subscribe @buffer, "modified-status-changed", => @emit "modified-status-changed"
+    @subscribe @buffer, "destroyed", => @destroy()
     @preserveCursorPositionOnBufferReload()
 
   # Private:
diff --git a/src/pane.coffee b/src/pane.coffee
index 5fadee731..acdc152d6 100644
--- a/src/pane.coffee
+++ b/src/pane.coffee
@@ -31,6 +31,7 @@ class Pane extends View
 
   # Private:
   initialize: (args...) ->
+    @items = []
     if args[0] instanceof telepath.Document
       @state = args[0]
       @items = _.compact @state.get('items').map (item) ->
@@ -43,6 +44,8 @@ class Pane extends View
         deserializer: 'Pane'
         items: @items.map (item) -> item.getState?() ? item.serialize()
 
+    @handleItemEvents(item) for item in @items
+
     @subscribe @state.get('items'), 'changed', ({index, removedValues, insertedValues, siteId}) =>
       return if siteId is @state.siteId
       for itemState in removedValues
@@ -188,8 +191,14 @@ class Pane extends View
     @state.get('items').splice(index, 0, item.getState?() ? item.serialize()) if options.updateState ? true
     @items.splice(index, 0, item)
     @trigger 'pane:item-added', [item, index]
+    @handleItemEvents(item)
     item
 
+  handleItemEvents: (item) ->
+    if _.isFunction(item.on)
+      @subscribe item, 'destroyed', =>
+        @destroyItem(item) if @state.isAlive()
+
   # Public: Remove the currently active item.
   destroyActiveItem: =>
     @destroyItem(@activeItem)
@@ -197,11 +206,11 @@ class Pane extends View
 
   # Public: Remove the specified item.
   destroyItem: (item) ->
+    @unsubscribe(item) if _.isFunction(item.off)
     @trigger 'pane:before-item-destroyed', [item]
-    container = @getContainer()
 
     if @promptToSaveItem(item)
-      container.itemDestroyed(item)
+      @getContainer()?.itemDestroyed(item)
       @removeItem(item)
       item.destroy?()
       true
diff --git a/src/project.coffee b/src/project.coffee
index 27f3c0880..eae064fd6 100644
--- a/src/project.coffee
+++ b/src/project.coffee
@@ -4,11 +4,10 @@ url = require 'url'
 _ = require 'underscore-plus'
 fs = require 'fs-plus'
 Q = require 'q'
-telepath = require 'telepath'
+{Model} = require 'telepath'
 
 TextBuffer = require './text-buffer'
 Editor = require './editor'
-{Emitter} = require 'emissary'
 Directory = require './directory'
 Task = require './task'
 Git = require './git'
@@ -18,8 +17,7 @@ Git = require './git'
 # Ultimately, a project is a git directory that's been opened. It's a collection
 # of directories and files that you can operate on.
 module.exports =
-class Project extends telepath.Model
-  Emitter.includeInto(this)
+class Project extends Model
 
   @properties
     buffers: []
diff --git a/src/text-buffer.coffee b/src/text-buffer.coffee
index d84ee24da..b5936c8fb 100644
--- a/src/text-buffer.coffee
+++ b/src/text-buffer.coffee
@@ -1,5 +1,5 @@
 _ = require 'underscore-plus'
-{Emitter, Subscriber} = require 'emissary'
+diff = require 'diff'
 Q = require 'q'
 {P} = require 'scandal'
 telepath = require 'telepath'
@@ -14,9 +14,6 @@ File = require './file'
 # the case, as a `TextBuffer` could be an unsaved chunk of text.
 module.exports =
 class TextBuffer extends telepath.Model
-  Emitter.includeInto(this)
-  Subscriber.includeInto(this)
-
   @properties
     text: -> new telepath.String('', replicated: false)
     filePath: null
@@ -87,7 +84,6 @@ class TextBuffer extends telepath.Model
       @file?.off()
       @unsubscribe()
       @alreadyDestroyed = true
-      @emit 'destroyed', this
 
   isRetained: -> @refcount > 0
 
@@ -117,8 +113,12 @@ class TextBuffer extends telepath.Model
         @reload()
 
     @file.on "removed", =>
-      @updateCachedDiskContents().done =>
-        @emitModifiedStatusChanged(@isModified())
+      modified = @getText() != @cachedDiskContents
+      @wasModifiedBeforeRemove = modified
+      if modified
+        @updateCachedDiskContents()
+      else
+        @destroy()
 
     @file.on "moved", =>
       @emit "path-changed", this
@@ -137,7 +137,7 @@ class TextBuffer extends telepath.Model
   # Sets the buffer's content to the cached disk contents
   reload: ->
     @emit 'will-reload'
-    @setText(@cachedDiskContents)
+    @setTextViaDiff(@cachedDiskContents)
     @emitModifiedStatusChanged(false)
     @emit 'reloaded'
 
@@ -202,6 +202,52 @@ class TextBuffer extends telepath.Model
   setText: (text) ->
     @change(@getRange(), text, normalizeLineEndings: false)
 
+  # Private: Replaces the current buffer contents. Only apply the differences.
+  #
+  # text - A {String} containing the new buffer contents.
+  setTextViaDiff: (text) ->
+    currentText = @getText()
+    return if currentText == text
+
+    endsWithNewline = (str) ->
+      /[\r\n]+$/g.test(str)
+
+    computeBufferColumn = (str) ->
+      newlineIndex = Math.max(str.lastIndexOf('\n'), str.lastIndexOf('\r'))
+      if endsWithNewline(str)
+        0
+      else if newlineIndex == -1
+        str.length
+      else
+        str.length - newlineIndex - 1
+
+    @transact =>
+      row = 0
+      column = 0
+      currentPosition = [0, 0]
+
+      lineDiff = diff.diffLines(currentText, text)
+      changeOptions = normalizeLineEndings: false
+
+      for change in lineDiff
+        lineCount = change.value.match(/\n/g)?.length ? 0
+        currentPosition[0] = row
+        currentPosition[1] = column
+
+        if change.added
+          @change([currentPosition, currentPosition], change.value, changeOptions)
+          row += lineCount
+          column = computeBufferColumn(change.value)
+
+        else if change.removed
+          endRow = row + lineCount
+          endColumn = column + computeBufferColumn(change.value)
+          @change([currentPosition, [endRow, endColumn]], '', changeOptions)
+
+        else
+          row += lineCount
+          column = computeBufferColumn(change.value)
+
   # Gets the range of the buffer contents.
   #
   # Returns a new {Range}, from `[0, 0]` to the end of the buffer.
@@ -403,7 +449,7 @@ class TextBuffer extends telepath.Model
       if @file.exists()
         @getText() != @cachedDiskContents
       else
-        true
+        @wasModifiedBeforeRemove ? not @isEmpty()
     else
       not @isEmpty()