diff --git a/spec/workspace-spec.coffee b/spec/workspace-spec.coffee
index 937069482..4ca654d18 100644
--- a/spec/workspace-spec.coffee
+++ b/spec/workspace-spec.coffee
@@ -7,49 +7,119 @@ describe "Workspace", ->
     atom.project.setPath(atom.project.resolve('dir'))
     workspace = new Workspace
 
-  describe "::open(uri)", ->
+  describe "::open(uri, options)", ->
     beforeEach ->
-      spyOn(workspace.activePane, 'activate')
-
-    describe "when called without a uri", ->
-      it "adds and activates an empty editor on the active pane", ->
-        editor = null
-        waitsForPromise ->
-          workspace.open().then (o) -> editor = o
-
-        runs ->
-          expect(editor.getPath()).toBeUndefined()
-          expect(workspace.activePane.items).toEqual [editor]
-          expect(workspace.activePaneItem).toBe editor
-          expect(workspace.activePane.activate).toHaveBeenCalled()
-
-    describe "when called with a uri", ->
-      describe "when the active pane already has an editor for the given uri", ->
-        it "activates the existing editor on the active pane", ->
-          editor1 = workspace.openSync('a')
-          editor2 = workspace.openSync('b')
+      spyOn(workspace.activePane, 'activate').andCallThrough()
 
+    describe "when the 'searchAllPanes' option is false (default)", ->
+      describe "when called without a uri", ->
+        it "adds and activates an empty editor on the active pane", ->
           editor = null
           waitsForPromise ->
-            workspace.open('a').then (o) -> editor = o
+            workspace.open().then (o) -> editor = o
 
           runs ->
-            expect(editor).toBe editor1
-            expect(workspace.activePaneItem).toBe editor
-            expect(workspace.activePane.activate).toHaveBeenCalled()
-
-      describe "when the active pane does not have an editor for the given uri", ->
-        it "adds and activates a new editor for the given path on the active pane", ->
-          editor = null
-          waitsForPromise ->
-            workspace.open('a').then (o) -> editor = o
-
-          runs ->
-            expect(editor.getUri()).toBe 'a'
-            expect(workspace.activePaneItem).toBe editor
+            expect(editor.getPath()).toBeUndefined()
             expect(workspace.activePane.items).toEqual [editor]
+            expect(workspace.activePaneItem).toBe editor
             expect(workspace.activePane.activate).toHaveBeenCalled()
 
+      describe "when called with a uri", ->
+        describe "when the active pane already has an editor for the given uri", ->
+          it "activates the existing editor on the active pane", ->
+            editor1 = workspace.openSync('a')
+            editor2 = workspace.openSync('b')
+
+            editor = null
+            waitsForPromise ->
+              workspace.open('a').then (o) -> editor = o
+
+            runs ->
+              expect(editor).toBe editor1
+              expect(workspace.activePaneItem).toBe editor
+              expect(workspace.activePane.activate).toHaveBeenCalled()
+
+        describe "when the active pane does not have an editor for the given uri", ->
+          it "adds and activates a new editor for the given path on the active pane", ->
+            editor = null
+            waitsForPromise ->
+              workspace.open('a').then (o) -> editor = o
+
+            runs ->
+              expect(editor.getUri()).toBe 'a'
+              expect(workspace.activePaneItem).toBe editor
+              expect(workspace.activePane.items).toEqual [editor]
+              expect(workspace.activePane.activate).toHaveBeenCalled()
+
+    describe "when the 'searchAllPanes' option is true", ->
+      describe "when an editor for the given uri is already open on an inactive pane", ->
+        it "activates the existing editor on the inactive pane, then activates that pane", ->
+          editor1 = workspace.openSync('a')
+          pane1 = workspace.activePane
+          pane2 = workspace.activePane.splitRight()
+          editor2 = workspace.openSync('b')
+          expect(workspace.activePaneItem).toBe editor2
+
+          waitsForPromise ->
+            workspace.open('a', searchAllPanes: true)
+
+          runs ->
+            expect(workspace.activePane).toBe pane1
+            expect(workspace.activePaneItem).toBe editor1
+
+      describe "when no editor for the given uri is open in any pane", ->
+        it "opens an editor for the given uri in the active pane", ->
+          editor = null
+          waitsForPromise ->
+            workspace.open('a', searchAllPanes: true).then (o) -> editor = o
+
+          runs ->
+            expect(workspace.activePaneItem).toBe editor
+
+    describe "when the 'split' option is set", ->
+      describe "when the 'split' option is 'left'", ->
+        it "opens the editor in the leftmost pane of the current pane axis", ->
+          pane1 = workspace.activePane
+          pane2 = pane1.splitRight()
+          expect(workspace.activePane).toBe pane2
+
+          editor = null
+          waitsForPromise ->
+            workspace.open('a', split: 'left').then (o) -> editor = o
+
+          runs ->
+            expect(workspace.activePane).toBe pane1
+            expect(pane1.items).toEqual [editor]
+            expect(pane2.items).toEqual []
+
+      describe "when the 'split' option is 'right'", ->
+        it "activates the editor on the existing right pane", ->
+          pane1 = workspace.activePane
+          pane2 = pane1.splitRight()
+          pane1.activate()
+
+          editor = null
+          waitsForPromise ->
+            workspace.open('a', split: 'right').then (o) -> editor = o
+
+          runs ->
+            expect(workspace.activePane).toBe pane2
+            expect(pane2.items).toEqual [editor]
+            expect(pane1.items).toEqual []
+
+        it "splits the current pane if the right pane doesn't exist", ->
+          pane1 = workspace.activePane
+
+          editor = null
+          waitsForPromise ->
+            workspace.open('a', split: 'right').then (o) -> editor = o
+
+          runs ->
+            pane2 = workspace.activePane
+            expect(workspace.paneContainer.root.children).toEqual [pane1, pane2]
+            expect(pane2.items).toEqual [editor]
+            expect(pane1.items).toEqual []
+
   describe "::openSync(uri, options)", ->
     [activePane, initialItemCount] = []
 
@@ -92,61 +162,6 @@ describe "Workspace", ->
         workspace.openSync('b', activatePane: false)
         expect(activePane.activate).not.toHaveBeenCalled()
 
-  describe "::openSingletonSync(uri, options)", ->
-    describe "when an editor for the given uri is already open on the active pane", ->
-      it "activates the existing editor", ->
-        editor1 = workspace.openSync('a')
-        editor2 = workspace.openSync('b')
-        expect(workspace.activePaneItem).toBe editor2
-        workspace.openSingletonSync('a')
-        expect(workspace.activePaneItem).toBe editor1
-
-    describe "when an editor for the given uri is already open on an inactive pane", ->
-      it "activates the existing editor on the inactive pane, then activates that pane", ->
-        editor1 = workspace.openSync('a')
-        pane1 = workspace.activePane
-        pane2 = workspace.activePane.splitRight()
-        editor2 = workspace.openSync('b')
-        expect(workspace.activePaneItem).toBe editor2
-        workspace.openSingletonSync('a')
-        expect(workspace.activePane).toBe pane1
-        expect(workspace.activePaneItem).toBe editor1
-
-    describe "when no editor for the given uri is open in any pane", ->
-      it "opens an editor for the given uri in the active pane", ->
-        editor1 = workspace.openSingletonSync('a')
-        expect(workspace.activePaneItem).toBe editor1
-
-      describe "when the 'split' option is 'left'", ->
-        it "opens the editor in the leftmost pane of the current pane axis", ->
-          pane1 = workspace.activePane
-          pane2 = pane1.splitRight()
-          expect(workspace.activePane).toBe pane2
-          editor1 = workspace.openSingletonSync('a', split: 'left')
-          expect(workspace.activePane).toBe pane1
-          expect(pane1.items).toEqual [editor1]
-          expect(pane2.items).toEqual []
-
-      describe "when the 'split' option is 'right'", ->
-        describe "when the active pane is in a horizontal pane axis", ->
-          it "activates the editor on the rightmost pane of the current pane axis", ->
-            pane1 = workspace.activePane
-            pane2 = pane1.splitRight()
-            pane1.activate()
-            editor1 = workspace.openSingletonSync('a', split: 'right')
-            expect(workspace.activePane).toBe pane2
-            expect(pane2.items).toEqual [editor1]
-            expect(pane1.items).toEqual []
-
-        describe "when the active pane is not in a horizontal pane axis", ->
-          it "splits the current pane to the right, then activates the editor on the right pane", ->
-            pane1 = workspace.activePane
-            editor1 = workspace.openSingletonSync('a', split: 'right')
-            pane2 = workspace.activePane
-            expect(workspace.paneContainer.root.children).toEqual [pane1, pane2]
-            expect(pane2.items).toEqual [editor1]
-            expect(pane1.items).toEqual []
-
   describe "::reopenItemSync()", ->
     it "opens the uri associated with the last closed pane that isn't currently open", ->
       pane = workspace.activePane
diff --git a/src/workspace.coffee b/src/workspace.coffee
index 21663bb59..c3d9cb48d 100644
--- a/src/workspace.coffee
+++ b/src/workspace.coffee
@@ -57,20 +57,30 @@ class Workspace extends Model
     changeFocus = options.changeFocus ? true
     filePath = atom.project.resolve(filePath)
     initialLine = options.initialLine
-    activePane = @activePane
+    searchAllPanes = options.searchAllPanes
+    split = options.split
+    uri = atom.project.relativize(filePath)
 
-    editor = activePane.itemForUri(atom.project.relativize(filePath)) if activePane and filePath
-    promise = atom.project.open(filePath, {initialLine}) if not editor
+    pane = switch split
+      when 'left'
+        @activePane.findLeftmostSibling()
+      when 'right'
+        @activePane.findOrCreateRightmostSibling()
+      else
+        if searchAllPanes
+          @paneContainer.paneForUri(uri) ? @activePane
+        else
+          @activePane
 
-    Q(editor ? promise)
+    Q(pane.itemForUri(uri) ? atom.project.open(filePath, options))
       .then (editor) =>
-        if not activePane
-          activePane = new Pane(items: [editor])
-          @paneContainer.root = activePane
+        if not pane
+          pane = new Pane(items: [editor])
+          @paneContainer.root = pane
 
         @itemOpened(editor)
-        activePane.activateItem(editor)
-        activePane.activate() if changeFocus
+        pane.activateItem(editor)
+        pane.activate() if changeFocus
         @emit "uri-opened"
         editor
       .catch (error) ->