diff --git a/services/document-updater/app/coffee/RangesTracker.coffee b/services/document-updater/app/coffee/RangesTracker.coffee
index 1b865a600d..233f5ad989 100644
--- a/services/document-updater/app/coffee/RangesTracker.coffee
+++ b/services/document-updater/app/coffee/RangesTracker.coffee
@@ -35,18 +35,25 @@ load = (EventEmitter) ->
 		#   * Inserts by another user will not combine with inserts by the first user. If they are in the
 		#     middle of a previous insert by the first user, the original insert will be split into two.
 		constructor: (@changes = [], @comments = []) ->
-			# Change objects have the following structure:
-			# {
-			#   id: ... # Uniquely generated by us
-			#   op: { # ShareJs style op tracking the offset (p) and content inserted (i) or deleted (d)
-			#     i: "..."
-			#     p: 42
-			#   }
-			# }
-			#
-			# Ids are used to uniquely identify a change, e.g. for updating it in the database, or keeping in
-			# sync with Ace ranges.
-			@id = 0
+
+		@_increment: 0
+		@newId: () ->
+			# Generate a Mongo ObjectId
+			# Reference: https://github.com/dreampulse/ObjectId.js/blob/master/src/main/javascript/Objectid.js
+			@_pid ?= Math.floor(Math.random() * (32767))
+			@_machine ?= Math.floor(Math.random() * (16777216))
+			timestamp = Math.floor(new Date().valueOf() / 1000)
+			@_increment++
+			
+			timestamp = timestamp.toString(16)
+			machine = @_machine.toString(16)
+			pid = @_pid.toString(16)
+			increment = @_increment.toString(16)
+			
+			return '00000000'.substr(0, 8 - timestamp.length) + timestamp +
+				'000000'.substr(0, 6 - machine.length) + machine +
+				'0000'.substr(0, 4 - pid.length) + pid +
+				'000000'.substr(0, 6 - increment.length) + increment;
 		
 		getComment: (comment_id) ->
 			comment = null
@@ -56,19 +63,6 @@ load = (EventEmitter) ->
 					break
 			return comment
 		
-		resolveCommentId: (comment_id, resolved_data) ->
-			comment = @getComment(comment_id)
-			return if !comment?
-			comment.metadata.resolved = true
-			comment.metadata.resolved_data = resolved_data
-			@emit "comment:resolved", comment
-		
-		unresolveCommentId: (comment_id) ->
-			comment = @getComment(comment_id)
-			return if !comment?
-			comment.metadata.resolved = false
-			@emit "comment:unresolved", comment
-		
 		removeCommentId: (comment_id) ->
 			comment = @getComment(comment_id)
 			return if !comment?
@@ -88,7 +82,7 @@ load = (EventEmitter) ->
 			return if !change?
 			@_removeChange(change)
 
-		applyOp: (op, metadata) ->
+		applyOp: (op, metadata = {}) ->
 			metadata.ts ?= new Date()
 			# Apply an op that has been applied to the document to our changes to keep them up to date
 			if op.i?
@@ -97,6 +91,8 @@ load = (EventEmitter) ->
 			else if op.d?
 				@applyDeleteToChanges(op, metadata)
 				@applyDeleteToComments(op)
+			else if op.dr?
+				@applyDeleteRangeToChanges(op)
 			else if op.c?
 				@addComment(op, metadata)
 			else
@@ -105,7 +101,7 @@ load = (EventEmitter) ->
 		addComment: (op, metadata) ->
 			# TODO: Don't allow overlapping comments?
 			@comments.push comment = {
-				id: @_newId()
+				id: RangesTracker.newId()
 				op: # Copy because we'll modify in place
 					c: op.c
 					p: op.p
@@ -394,28 +390,20 @@ load = (EventEmitter) ->
 			if moved_changes.length > 0
 				@emit "changes:moved", moved_changes
 
-		_newId: () ->
-			# Generate a Mongo ObjectId
-			# Reference: https://github.com/dreampulse/ObjectId.js/blob/master/src/main/javascript/Objectid.js
-			@_pid ?= Math.floor(Math.random() * (32767))
-			@_machine ?= Math.floor(Math.random() * (16777216))
-			timestamp = Math.floor(new Date().valueOf() / 1000)
-			@_increment ?= 0
-			@_increment++
-			
-			timestamp = timestamp.toString(16)
-			machine = @_machine.toString(16)
-			pid = @_pid.toString(16)
-			increment = @_increment.toString(16)
-			
-			return '00000000'.substr(0, 8 - timestamp.length) + timestamp +
-				'000000'.substr(0, 6 - machine.length) + machine +
-				'0000'.substr(0, 4 - pid.length) + pid +
-				'000000'.substr(0, 6 - increment.length) + increment;
+		applyDeleteRangeToChanges: (op) ->
+			remove_changes = []
+			for change in @changes
+				change_text = change.op.i or change.op.d
+				if op.p == change.op.p and op.dr == change_text
+					remove_changes.push change
+			if remove_changes.length == 0
+				throw new Error("no range to remove")
+			for change in remove_changes
+				@_removeChange(change)
 
 		_addOp: (op, metadata) ->
 			change = {
-				id: @_newId()
+				id: RangesTracker.newId()
 				op: op
 				metadata: metadata
 			}
diff --git a/services/document-updater/app/coffee/sharejs/types/text.coffee b/services/document-updater/app/coffee/sharejs/types/text.coffee
index 2a3b79997d..84303b3307 100644
--- a/services/document-updater/app/coffee/sharejs/types/text.coffee
+++ b/services/document-updater/app/coffee/sharejs/types/text.coffee
@@ -32,7 +32,8 @@ checkValidComponent = (c) ->
   i_type = typeof c.i
   d_type = typeof c.d
   c_type = typeof c.c
-  throw new Error 'component needs an i, d or c field' unless (i_type == 'string') ^ (d_type == 'string') ^ (c_type == 'string')
+  dr_type = typeof c.dr
+  throw new Error 'component needs an i, d, c or dr field' unless (i_type == 'string') ^ (d_type == 'string') ^ (c_type == 'string') ^ (dr_type == 'string')
 
   throw new Error 'position cannot be negative' unless c.p >= 0
 
@@ -40,6 +41,26 @@ checkValidOp = (op) ->
   checkValidComponent(c) for c in op
   true
 
+componentText = (c) ->
+  if c.c?
+    text = c.c
+  if c.dr?
+    text = c.dr
+  throw new Error("invalid component") if !text?
+  return text
+
+duplicateComponent = (c) ->
+  newC = {}
+  for key, value of c
+    newC[key] = value
+  return newC
+
+setComponentText = (c, text) ->
+  if c.c?
+    c.c = text
+  if c.dr?
+    c.dr = text
+
 text.apply = (snapshot, op) ->
   checkValidOp op
   for component in op
@@ -49,9 +70,10 @@ text.apply = (snapshot, op) ->
       deleted = snapshot[component.p...(component.p + component.d.length)]
       throw new Error "Delete component '#{component.d}' does not match deleted text '#{deleted}'" unless component.d == deleted
       snapshot = snapshot[...component.p] + snapshot[(component.p + component.d.length)..]
-    else if component.c?
-      comment = snapshot[component.p...(component.p + component.c.length)]
-      throw new Error "Comment component '#{component.c}' does not match commented text '#{comment}'" unless component.c == comment
+    else if component.c? or component.dr?
+      c_text = componentText(component)
+      range = snapshot[component.p...(component.p + c_text.length)]
+      throw new Error "Range component '#{c_text}' does not match range text '#{range}'" unless c_text == range
     else
       throw new Error "Unknown op type"
   snapshot
@@ -127,7 +149,7 @@ transformPosition = (pos, c, insertAfter) ->
       c.p
     else
       pos - c.d.length
-  else if c.c?
+  else if c.c? or c.dr?
     pos
   else
     throw new Error("unknown op type")
@@ -187,46 +209,54 @@ text._tc = transformComponent = (dest, c, otherC, side) ->
           newC.p = transformPosition newC.p, otherC
           append dest, newC
     
-    else if otherC.c?
+    else if otherC.c? or otherC.dr?
       append dest, c
     
     else
       throw new Error("unknown op type")
 
-  else if c.c? # Comment
+  else if c.c? or c.dr? # Comment or delete range
+    c_text = componentText(c)
     if otherC.i?
-      if c.p < otherC.p < c.p + c.c.length
+      if c.p < otherC.p < c.p + c_text.length
         offset = otherC.p - c.p
-        new_c = (c.c[0..(offset-1)] + otherC.i + c.c[offset...])
-        append dest, {c:new_c, p:c.p, t: c.t}
+        newText = (c_text[0..(offset-1)] + otherC.i + c_text[offset...])
+        newC = duplicateComponent(c)
+        setComponentText(newC, newText)
+        append dest, newC
       else
-        append dest, {c:c.c, p:transformPosition(c.p, otherC, true), t: c.t}
+        newC = duplicateComponent(c)
+        newC.p = transformPosition(c.p, otherC, true)
+        append dest, newC
     
     else if otherC.d?
       if c.p >= otherC.p + otherC.d.length
-        append dest, {c:c.c, p:c.p - otherC.d.length, t: c.t}
-      else if c.p + c.c.length <= otherC.p
+        newC = duplicateComponent(c)
+        newC.p = c.p - otherC.d.length
+        append dest, newC
+      else if c.p + c_text.length <= otherC.p
         append dest, c
       else # Delete overlaps comment
         # They overlap somewhere.
-        newC = {c:'', p:c.p, t: c.t}
+        newC = duplicateComponent(c)
+        setComponentText(newC, '')
         if c.p < otherC.p
-          newC.c = c.c[...(otherC.p - c.p)]
-        if c.p + c.c.length > otherC.p + otherC.d.length
-          newC.c += c.c[(otherC.p + otherC.d.length - c.p)..]
+          setComponentText(newC, c_text[...(otherC.p - c.p)])
+        if c.p + c_text.length > otherC.p + otherC.d.length
+          setComponentText(newC, componentText(newC) + c_text[(otherC.p + otherC.d.length - c.p)..])
 
         # This is entirely optional - just for a check that the deleted
         # text in the two ops matches
         intersectStart = Math.max c.p, otherC.p
-        intersectEnd = Math.min c.p + c.c.length, otherC.p + otherC.d.length
-        cIntersect = c.c[intersectStart - c.p...intersectEnd - c.p]
+        intersectEnd = Math.min c.p + c_text.length, otherC.p + otherC.d.length
+        cIntersect = c_text[intersectStart - c.p...intersectEnd - c.p]
         otherIntersect = otherC.d[intersectStart - otherC.p...intersectEnd - otherC.p]
-        throw new Error 'Delete ops delete different text in the same region of the document' unless cIntersect == otherIntersect
+        throw new Error 'Delete op text does not match range being modified' unless cIntersect == otherIntersect
 
         newC.p = transformPosition newC.p, otherC
         append dest, newC
     
-    else if otherC.c?
+    else if otherC.c? or otherC.dr?
       append dest, c
     
     else
diff --git a/services/document-updater/test/acceptance/coffee/RangesTests.coffee b/services/document-updater/test/acceptance/coffee/RangesTests.coffee
index 0cee1598aa..a5cbee7569 100644
--- a/services/document-updater/test/acceptance/coffee/RangesTests.coffee
+++ b/services/document-updater/test/acceptance/coffee/RangesTests.coffee
@@ -1,6 +1,7 @@
 sinon = require "sinon"
 chai = require("chai")
 chai.should()
+expect = chai.expect
 async = require "async"
 rclient = require("redis").createClient()
 
@@ -54,82 +55,105 @@ describe "Ranges", ->
 				change.op.should.deep.equal { i: "456", p: 3 }
 				change.metadata.user_id.should.equal @user_id
 				done()
+		
+		describe "removing ranges", ->
+			it "should delete the range (and perform OT)", (done) ->
+				@conflicting_update = {
+					doc: @doc.id
+					op: [{ i: "X", p: 1 }]
+					v: 3
+					meta: { user_id: @user_id }
+				}
+				@delete_range = {
+					doc: @doc.id
+					op: [{ dr: "456", p: 3 }]
+					v: 3
+					meta: { user_id: @user_id }
+				}
+				DocUpdaterClient.sendUpdate @project_id, @doc.id, @conflicting_update, (error) =>
+					throw error if error?
+					DocUpdaterClient.sendUpdate @project_id, @doc.id, @delete_range, (error) =>
+						throw error if error?
+						DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
+							throw error if error?
+							expect(data.ranges.changes).to.be.undefined
+							done()
 	
-		describe "Adding comments", ->
-			describe "standalone", ->
-				before (done) ->
-					@project_id = DocUpdaterClient.randomId()
-					@user_id = DocUpdaterClient.randomId()
-					@doc = {
-						id: DocUpdaterClient.randomId()
-						lines: ["foo bar baz"]
-					}
-					@updates = [{
-						doc: @doc.id
-						op: [{ c: "bar", p: 4, t: @tid = DocUpdaterClient.randomId() }]
-						v: 0
-					}]
-					MockWebApi.insertDoc @project_id, @doc.id, {
-						lines: @doc.lines
-						version: 0
-					}
-					jobs = []
-					for update in @updates
-						do (update) =>
-							jobs.push (callback) => DocUpdaterClient.sendUpdate @project_id, @doc.id, update, callback
-					DocUpdaterClient.preloadDoc @project_id, @doc.id, (error) =>
+	describe "Adding comments", ->
+		describe "standalone", ->
+			before (done) ->
+				@project_id = DocUpdaterClient.randomId()
+				@user_id = DocUpdaterClient.randomId()
+				@doc = {
+					id: DocUpdaterClient.randomId()
+					lines: ["foo bar baz"]
+				}
+				@updates = [{
+					doc: @doc.id
+					op: [{ c: "bar", p: 4, t: @tid = DocUpdaterClient.randomId() }]
+					v: 0
+				}]
+				MockWebApi.insertDoc @project_id, @doc.id, {
+					lines: @doc.lines
+					version: 0
+				}
+				jobs = []
+				for update in @updates
+					do (update) =>
+						jobs.push (callback) => DocUpdaterClient.sendUpdate @project_id, @doc.id, update, callback
+				DocUpdaterClient.preloadDoc @project_id, @doc.id, (error) =>
+					throw error if error?
+					async.series jobs, (error) ->
 						throw error if error?
-						async.series jobs, (error) ->
-							throw error if error?
-							setTimeout done, 200
-				
-				it "should update the ranges", (done) ->
-					DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
-						throw error if error?
-						ranges = data.ranges
-						comment = ranges.comments[0]
-						comment.op.should.deep.equal { c: "bar", p: 4, t: @tid }
-						done()
+						setTimeout done, 200
+			
+			it "should update the ranges", (done) ->
+				DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
+					throw error if error?
+					ranges = data.ranges
+					comment = ranges.comments[0]
+					comment.op.should.deep.equal { c: "bar", p: 4, t: @tid }
+					done()
 
-			describe "with conflicting ops needing OT", ->
-				before (done) ->
-					@project_id = DocUpdaterClient.randomId()
-					@user_id = DocUpdaterClient.randomId()
-					@doc = {
-						id: DocUpdaterClient.randomId()
-						lines: ["foo bar baz"]
-					}
-					@updates = [{
-						doc: @doc.id
-						op: [{ i: "ABC", p: 3 }]
-						v: 0
-						meta: { user_id: @user_id }
-					}, {
-						doc: @doc.id
-						op: [{ c: "bar", p: 4, t: @tid = DocUpdaterClient.randomId() }]
-						v: 0
-					}]
-					MockWebApi.insertDoc @project_id, @doc.id, {
-						lines: @doc.lines
-						version: 0
-					}
-					jobs = []
-					for update in @updates
-						do (update) =>
-							jobs.push (callback) => DocUpdaterClient.sendUpdate @project_id, @doc.id, update, callback
-					DocUpdaterClient.preloadDoc @project_id, @doc.id, (error) =>
+		describe "with conflicting ops needing OT", ->
+			before (done) ->
+				@project_id = DocUpdaterClient.randomId()
+				@user_id = DocUpdaterClient.randomId()
+				@doc = {
+					id: DocUpdaterClient.randomId()
+					lines: ["foo bar baz"]
+				}
+				@updates = [{
+					doc: @doc.id
+					op: [{ i: "ABC", p: 3 }]
+					v: 0
+					meta: { user_id: @user_id }
+				}, {
+					doc: @doc.id
+					op: [{ c: "bar", p: 4, t: @tid = DocUpdaterClient.randomId() }]
+					v: 0
+				}]
+				MockWebApi.insertDoc @project_id, @doc.id, {
+					lines: @doc.lines
+					version: 0
+				}
+				jobs = []
+				for update in @updates
+					do (update) =>
+						jobs.push (callback) => DocUpdaterClient.sendUpdate @project_id, @doc.id, update, callback
+				DocUpdaterClient.preloadDoc @project_id, @doc.id, (error) =>
+					throw error if error?
+					async.series jobs, (error) ->
 						throw error if error?
-						async.series jobs, (error) ->
-							throw error if error?
-							setTimeout done, 200
-				
-				it "should update the comments with the OT shifted comment", (done) ->
-					DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
-						throw error if error?
-						ranges = data.ranges
-						comment = ranges.comments[0]
-						comment.op.should.deep.equal { c: "bar", p: 7, t: @tid }
-						done()
+						setTimeout done, 200
+			
+			it "should update the comments with the OT shifted comment", (done) ->
+				DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
+					throw error if error?
+					ranges = data.ranges
+					comment = ranges.comments[0]
+					comment.op.should.deep.equal { c: "bar", p: 7, t: @tid }
+					done()
 
 	describe "Loading ranges from persistence layer", ->
 		before (done) ->
diff --git a/services/document-updater/test/unit/coffee/ShareJS/TextTransformTests.coffee b/services/document-updater/test/unit/coffee/ShareJS/TextTransformTests.coffee
index 81440bfe5b..2d9dcf94a0 100644
--- a/services/document-updater/test/unit/coffee/ShareJS/TextTransformTests.coffee
+++ b/services/document-updater/test/unit/coffee/ShareJS/TextTransformTests.coffee
@@ -189,6 +189,95 @@ describe "ShareJS text type", ->
 				dest = []
 				text._tc(dest, { c: "foo", p: 6 }, { c: "bar", p: 3 })
 				dest.should.deep.equal [{ c: "foo", p: 6 }]
+	
+		describe "comment / delete_range", ->
+			it "should not do anything", ->
+				dest = []
+				text._tc(dest, { c: "foo", p: 6 }, { dr: "bar", p: 3 })
+				dest.should.deep.equal [{ c: "foo", p: 6 }]
+		
+		describe "delete_range / insert", ->
+			it "with an insert before", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 9 }, { i: "bar", p: 3 })
+				dest.should.deep.equal [{ dr: "foo", p: 12 }]
+
+			it "with an insert after", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 3 }, { i: "bar", p: 9 })
+				dest.should.deep.equal [{ dr: "foo", p: 3 }]
+
+			it "with an insert at the left edge", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 3 }, { i: "bar", p: 3 })
+				# RangesTracker doesn't inject inserts into comments on edges, so neither should we
+				dest.should.deep.equal [{ dr: "foo", p: 6 }]
+
+			it "with an insert at the right edge", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 3 }, { i: "bar", p: 6 })
+				# RangesTracker doesn't inject inserts into comments on edges, so neither should we
+				dest.should.deep.equal [{ dr: "foo", p: 3 }]
+
+			it "with an insert in the middle", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 3 }, { i: "bar", p: 5 })
+				dest.should.deep.equal [{ dr: "fobaro", p: 3 }]
+	
+		describe "delete_range / delete", ->
+			it "with a delete before", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 9 }, { d: "bar", p: 3 })
+				dest.should.deep.equal [{ dr: "foo", p: 6 }]
+
+			it "with a delete after", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 3 }, { i: "bar", p: 9 })
+				dest.should.deep.equal [{ dr: "foo", p: 3 }]
+
+			it "with a delete overlapping the comment content before", ->
+				dest = []
+				text._tc(dest, { dr: "foobar", p: 6 }, { d: "123foo", p: 3 })
+				dest.should.deep.equal [{ dr: "bar", p: 3 }]
+
+			it "with a delete overlapping the comment content after", ->
+				dest = []
+				text._tc(dest, { dr: "foobar", p: 6 }, { d: "bar123", p: 9 })
+				dest.should.deep.equal [{ dr: "foo", p: 6 }]
+
+			it "with a delete overlapping the comment content in the middle", ->
+				dest = []
+				text._tc(dest, { dr: "foo123bar", p: 6 }, { d: "123", p: 9 })
+				dest.should.deep.equal [{ dr: "foobar", p: 6 }]
+
+			it "with a delete overlapping the whole comment", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 6 }, { d: "123foo456", p: 3 })
+				dest.should.deep.equal [{ dr: "", p: 3 }]
+	
+		describe "delete_range / insert", ->
+			it "should not do anything", ->
+				dest = []
+				text._tc(dest, { i: "foo", p: 6 }, { dr: "bar", p: 3 })
+				dest.should.deep.equal [{ i: "foo", p: 6 }]
+	
+		describe "delete_range / delete", ->
+			it "should not do anything", ->
+				dest = []
+				text._tc(dest, { d: "foo", p: 6 }, { dr: "bar", p: 3 })
+				dest.should.deep.equal [{ d: "foo", p: 6 }]
+	
+		describe "delete_range / comment", ->
+			it "should not do anything", ->
+				dest = []
+				text._tc(dest, { c: "foo", p: 6 }, { dr: "bar", p: 3 })
+				dest.should.deep.equal [{ c: "foo", p: 6 }]
+	
+		describe "delete_range / delete_range", ->
+			it "should not do anything", ->
+				dest = []
+				text._tc(dest, { dr: "foo", p: 6 }, { dr: "bar", p: 3 })
+				dest.should.deep.equal [{ dr: "foo", p: 6 }]
 
 	describe "apply", ->
 		it "should apply an insert", ->
@@ -199,6 +288,9 @@ describe "ShareJS text type", ->
 
 		it "should do nothing with a comment", ->
 			text.apply("foo123bar", [{ c: "123", p: 3 }]).should.equal "foo123bar"
+
+		it "should do nothing with a delete_range", ->
+			text.apply("foo123bar", [{ dr: "123", p: 3 }]).should.equal "foo123bar"
 		
 		it "should throw an error when deleted content does not match", ->
 			(() ->