diff --git a/spec/app/root-view-spec.coffee b/spec/app/root-view-spec.coffee
index eef34f027..3b4b24fa2 100644
--- a/spec/app/root-view-spec.coffee
+++ b/spec/app/root-view-spec.coffee
@@ -498,9 +498,101 @@ describe "RootView", ->
       rootView.trigger 'decrease-font-size'
       expect(rootView.getFontSize()).toBe fontSizeBefore
 
-  it "does not allow the font size to be less than 1", ->
-    rootView.setFontSize(1)
-    expect(rootView.getFontSize()).toBe 1
+    it "does not allow the font size to be less than 1", ->
+      rootView.setFontSize(1)
+      expect(rootView.getFontSize()).toBe 1
+
+      rootView.setFontSize(0)
+      expect(rootView.getFontSize()).toBe 1
+
+  describe ".open(path, options)", ->
+    describe "when there is no active editor", ->
+      beforeEach ->
+        rootView.activeEditor().removeActiveEditSession()
+        expect(rootView.activeEditor()).toBeUndefined()
+
+      describe "when called with no path", ->
+        it "opens an empty buffer in a new editor", ->
+          rootView.open()
+          expect(rootView.activeEditor()).toBeDefined()
+          expect(rootView.activeEditor().buffer.path).toBeUndefined()
+
+      describe "when called with a path", ->
+        it "opens a buffer with the given path in a new editor", ->
+          rootView.open('b')
+          expect(rootView.activeEditor()).toBeDefined()
+          expect(rootView.activeEditor().buffer.path).toBe require.resolve('fixtures/dir/b')
+
+    describe "when there is an active editor", ->
+      beforeEach ->
+        expect(rootView.activeEditor()).toBeDefined()
+
+      describe "when called with no path", ->
+        it "opens an empty buffer in the active editor", ->
+          rootView.open()
+          expect(rootView.activeEditor().buffer.path).toBeUndefined()
+
+      describe "when called with a path", ->
+        [editor1, editor2] = []
+        beforeEach ->
+          rootView.attachToDom()
+          editor1 = rootView.activeEditor()
+          editor2 = editor1.splitRight()
+          rootView.open('b')
+          editor2.loadPreviousEditSession()
+          editor1.focus()
+
+        describe "when allowActiveEditorChange is false (the default)", ->
+          activeEditor = null
+          beforeEach ->
+            activeEditor = rootView.activeEditor()
+
+          describe "when the active editor has an edit session for the given path", ->
+            it "re-activates the existing edit session", ->
+              expect(activeEditor.buffer.path).toBe require.resolve('fixtures/dir/a')
+              previousEditSession = activeEditor.activeEditSession
+
+              rootView.open('b')
+              expect(activeEditor.activeEditSession).not.toBe previousEditSession
+
+              rootView.open('a')
+              expect(activeEditor.activeEditSession).toBe previousEditSession
+
+          describe "when the active editor does not have an edit session for the given path", ->
+            it "creates a new edit session for the given path in the active editor", ->
+              rootView.open('b')
+              expect(activeEditor.editSessions.length).toBe 2
+
+        describe "when the 'allowActiveEditorChange' option is true", ->
+          describe "when the active editor has an edit session for the given path", ->
+            it "re-activates the existing edit session regardless of whether any other editor also has an edit session for the path", ->
+              activeEditor = rootView.activeEditor()
+              expect(activeEditor.buffer.path).toBe require.resolve('fixtures/dir/a')
+              previousEditSession = activeEditor.activeEditSession
+
+              rootView.open('b')
+              expect(activeEditor.activeEditSession).not.toBe previousEditSession
+
+              rootView.open('a', allowActiveEditorChange: true)
+              expect(activeEditor.activeEditSession).toBe previousEditSession
+
+          describe "when the active editor does *not* have an edit session for the given path", ->
+            describe "when another editor has an edit session for the path", ->
+              it "focuses the other editor and activates its edit session for the path", ->
+                expect(rootView.activeEditor()).toBe editor1
+                rootView.open('b', allowActiveEditorChange: true)
+                expect(rootView.activeEditor()).toBe editor2
+                expect(editor2.buffer.path).toBe require.resolve('fixtures/dir/b')
+
+            describe "when no other editor has an edit session for the path either", ->
+              it "creates a new edit session for the path on the current active editor", ->
+                path = require.resolve('fixtures/sample.js')
+                rootView.open(path, allowActiveEditorChange: true)
+                expect(rootView.activeEditor()).toBe editor1
+                expect(editor1.buffer.path).toBe path
+
+
+
+
+
 
-    rootView.setFontSize(0)
-    expect(rootView.getFontSize()).toBe 1
diff --git a/src/app/editor.coffee b/src/app/editor.coffee
index c43069817..ab229330c 100644
--- a/src/app/editor.coffee
+++ b/src/app/editor.coffee
@@ -389,6 +389,13 @@ class Editor extends View
 
     @renderWhenAttached()
 
+  activateEditSessionForPath: (path) ->
+    for editSession, index in @editSessions
+      if editSession.buffer.getPath() == path
+        @setActiveEditSessionIndex(index)
+        return true
+    false
+
   getOpenBufferPaths: ->
     editSession.buffer.path for editSession in @editSessions when editSession.buffer.path?
 
diff --git a/src/app/root-view.coffee b/src/app/root-view.coffee
index ae64fb066..dbb4bbd83 100644
--- a/src/app/root-view.coffee
+++ b/src/app/root-view.coffee
@@ -91,13 +91,12 @@ class RootView extends View
     extension.deactivate?() for name, extension of @extensions
     @remove()
 
-  open: (path, changeFocus=true) ->
-    editSession = @project.open(path)
+  open: (path, options = {}) ->
+    changeFocus = options.changeFocus ? true
+    allowActiveEditorChange = options.allowActiveEditorChange ? false
 
-    if @activeEditor()
-      @activeEditor().edit(editSession)
-    else
-      editor = new Editor(editSession: editSession)
+    unless @openInExistingEditor(path, allowActiveEditorChange)
+      editor = new Editor(editSession: @project.open(path))
       pane = new Pane(editor)
       @panes.append(pane)
       if changeFocus
@@ -105,6 +104,24 @@ class RootView extends View
       else
         @makeEditorActive(editor)
 
+  openInExistingEditor: (path, allowActiveEditorChange) ->
+    if activeEditor = @activeEditor()
+      path = @project.resolve(path) if path
+
+      if activeEditor.activateEditSessionForPath(path)
+        return true
+
+      if allowActiveEditorChange
+        for editor in @editors()
+          if editor.activateEditSessionForPath(path)
+            editor.focus()
+            return true
+
+      activeEditor.edit(@project.open(path))
+      true
+    else
+      false
+
   editorFocused: (editor) ->
     @makeEditorActive(editor) if @panes.containsElement(editor)
 
diff --git a/src/extensions/tree-view/tree-view.coffee b/src/extensions/tree-view/tree-view.coffee
index 50a18cffb..713ddbf83 100644
--- a/src/extensions/tree-view/tree-view.coffee
+++ b/src/extensions/tree-view/tree-view.coffee
@@ -156,7 +156,7 @@ class TreeView extends View
     if (selectedEntry instanceof DirectoryView)
       selectedEntry.view().toggleExpansion()
     else if (selectedEntry instanceof FileView)
-      @rootView.open(selectedEntry.getPath(), false)
+      @rootView.open(selectedEntry.getPath(), changeFocus: false)
 
   moveSelectedEntry: ->
     entry = @selectedEntry()