diff --git a/services/web/public/coffee/ide/editor/Document.coffee b/services/web/public/coffee/ide/editor/Document.coffee
index 1de01b5467..91c05e6e39 100644
--- a/services/web/public/coffee/ide/editor/Document.coffee
+++ b/services/web/public/coffee/ide/editor/Document.coffee
@@ -353,11 +353,12 @@ define [
 				@ranges.applyOp op, { user_id: track_changes_as }
 			if old_id_seed?
 				@ranges.setIdSeed(old_id_seed)
+			@emit "ranges:dirty"
 		
 		_catchUpRanges: (changes = [], comments = []) ->
 			# We've just been given the current server's ranges, but need to apply any local ops we have.
 			# Reset to the server state then apply our local ops again.
-			@ranges.emit "clear"
+			@emit "ranges:clear"
 			@ranges.changes = changes
 			@ranges.comments = comments
 			@ranges.track_changes = @doc.track_changes
@@ -367,4 +368,4 @@ define [
 			for op in @doc.getPendingOp() or []
 				@ranges.setIdSeed(@doc.track_changes_id_seeds.pending)
 				@ranges.applyOp(op, { user_id: @track_changes_as })
-			@ranges.emit "redraw"
+			@emit "ranges:redraw"
diff --git a/services/web/public/coffee/ide/editor/directives/aceEditor/track-changes/TrackChangesManager.coffee b/services/web/public/coffee/ide/editor/directives/aceEditor/track-changes/TrackChangesManager.coffee
index 38b3e5678c..17c10e7f71 100644
--- a/services/web/public/coffee/ide/editor/directives/aceEditor/track-changes/TrackChangesManager.coffee
+++ b/services/web/public/coffee/ide/editor/directives/aceEditor/track-changes/TrackChangesManager.coffee
@@ -14,11 +14,11 @@ define [
 				return if !track_changes?
 				@setTrackChanges(track_changes)
 			
-			@$scope.$watch "sharejsDoc", (doc) =>
+			@$scope.$watch "sharejsDoc", (doc, oldDoc) =>
 				return if !doc?
-				@disconnectFromRangesTracker()
-				@rangesTracker = doc.ranges
-				@connectToRangesTracker()
+				if oldDoc?
+					@disconnectFromDoc(oldDoc)
+				@connectToDoc(doc)
 			
 			@$scope.$on "comment:add", (e, thread_id, offset, length) =>
 				@addCommentToSelection(thread_id, offset, length)
@@ -36,10 +36,10 @@ define [
 				@removeCommentId(comment_id)
 			
 			@$scope.$on "comment:resolve_threads", (e, thread_ids) =>
-				@resolveCommentByThreadIds(thread_ids)
+				@hideCommentsByThreadIds(thread_ids)
 			
 			@$scope.$on "comment:unresolve_thread", (e, thread_id) =>
-				@unresolveCommentByThreadId(thread_id)
+				@showCommentByThreadId(thread_id)
 			
 			@$scope.$on "review-panel:recalculate-screen-positions", () =>
 				@recalculateReviewEntriesScreenPositions()
@@ -92,18 +92,11 @@ define [
 				else
 					unbindFromAce()
 		
-		disconnectFromRangesTracker: () ->
+		disconnectFromDoc: (doc) ->
 			@changeIdToMarkerIdMap = {}
-
-			if @rangesTracker?
-				@rangesTracker.off "insert:added"
-				@rangesTracker.off "insert:removed"
-				@rangesTracker.off "delete:added"
-				@rangesTracker.off "delete:removed"
-				@rangesTracker.off "changes:moved"
-				@rangesTracker.off "comment:added"
-				@rangesTracker.off "comment:moved"
-				@rangesTracker.off "comment:removed"
+			doc.off "ranges:clear"
+			doc.off "ranges:redraw"
+			doc.off "ranges:dirty"
 
 		setTrackChanges: (value) ->
 			if value
@@ -111,56 +104,15 @@ define [
 			else
 				@$scope.sharejsDoc?.track_changes_as = null
 		
-		connectToRangesTracker: () ->
+		connectToDoc: (doc) ->
+			@rangesTracker = doc.ranges
 			@setTrackChanges(@$scope.trackChanges)
 			
-			# Add a timeout because on remote ops, we get these notifications before
-			# ace has updated
-			@rangesTracker.on "insert:added", (change) =>
-				sl_console.log "[insert:added]", change
-				setTimeout () =>
-					@_onInsertAdded(change)
-					@broadcastChange()
-			@rangesTracker.on "insert:removed", (change) =>
-				sl_console.log "[insert:removed]", change
-				setTimeout () =>
-					@_onInsertRemoved(change)
-					@broadcastChange()
-			@rangesTracker.on "delete:added", (change) =>
-				sl_console.log "[delete:added]", change
-				setTimeout () =>
-					@_onDeleteAdded(change)
-					@broadcastChange()
-			@rangesTracker.on "delete:removed", (change) =>
-				sl_console.log "[delete:removed]", change
-				setTimeout () =>
-					@_onDeleteRemoved(change)
-					@broadcastChange()
-			@rangesTracker.on "changes:moved", (changes) =>
-				sl_console.log "[changes:moved]", changes
-				setTimeout () =>
-					@_onChangesMoved(changes)
-					@broadcastChange()
-
-			@rangesTracker.on "comment:added", (comment) =>
-				sl_console.log "[comment:added]", comment
-				setTimeout () =>
-					@_onCommentAdded(comment)
-					@broadcastChange()
-			@rangesTracker.on "comment:moved", (comment) =>
-				sl_console.log "[comment:moved]", comment
-				setTimeout () =>
-					@_onCommentMoved(comment)
-					@broadcastChange()
-			@rangesTracker.on "comment:removed", (comment) =>
-				sl_console.log "[comment:removed]", comment
-				setTimeout () =>
-					@_onCommentRemoved(comment)
-					@broadcastChange()
-			
-			@rangesTracker.on "clear", () =>
+			doc.on "ranges:dirty", () =>
+				@updateAnnotations()
+			doc.on "ranges:clear", () =>
 				@clearAnnotations()
-			@rangesTracker.on "redraw", () =>
+			doc.on "ranges:redraw", () =>
 				@redrawAnnotations()
 		
 		clearAnnotations: () ->
@@ -181,6 +133,55 @@ define [
 				@_onCommentAdded(comment)
 			
 			@broadcastChange()
+		
+		_doneUpdateThisLoop: false
+		_pendingUpdates: false
+		updateAnnotations: () ->
+			# Doc updates with multiple ops, like search/replace or block comments
+			# will call this with every individual op in a single event loop. So only
+			# do the first this loop, then schedule an update for the next loop for the rest.
+			if !@_doneUpdateThisLoop
+				@_doUpdateAnnotations()
+				@_doneUpdateThisLoop = true
+				setTimeout () =>
+					if @_pendingUpdates
+						@_doUpdateAnnotations()
+					@_doneUpdateThisLoop = false
+					@_pendingUpdates = false
+			else
+				@_pendingUpdates = true
+
+		_doUpdateAnnotations: () ->
+			dirty = @rangesTracker.getDirtyState()
+			
+			updateMarkers = false
+			
+			for id, change of dirty.change.added
+				if change.op.i?
+					@_onInsertAdded(change)
+				else if change.op.d?
+					@_onDeleteAdded(change)
+			for id, change of dirty.change.removed
+				if change.op.i?
+					@_onInsertRemoved(change)
+				else if change.op.d?
+					@_onDeleteRemoved(change)
+			for id, change of dirty.change.moved
+				updateMarkers = true
+				@_onChangeMoved(change)
+				
+			for id, comment of dirty.comment.added
+				@_onCommentAdded(comment)
+			for id, comment of dirty.comment.removed
+				@_onCommentRemoved(comment)
+			for id, comment of dirty.comment.moved
+				updateMarkers = true
+				@_onCommentMoved(comment)
+			
+			@rangesTracker.resetDirtyState()
+			if updateMarkers
+				@editor.renderer.updateBackMarkers()
+			@broadcastChange()
 
 		addComment: (offset, content, thread_id) ->
 			op = { c: content, p: offset, t: thread_id }
@@ -200,6 +201,7 @@ define [
 		
 		acceptChangeId: (change_id) ->
 			@rangesTracker.removeChangeId(change_id)
+			@updateAnnotations()
 		
 		rejectChangeId: (change_id) ->
 			change = @rangesTracker.getChange(change_id)
@@ -221,8 +223,9 @@ define [
 
 		removeCommentId: (comment_id) ->
 			@rangesTracker.removeCommentId(comment_id)
+			@updateAnnotations()
 
-		resolveCommentByThreadIds: (thread_ids) ->
+		hideCommentsByThreadIds: (thread_ids) ->
 			resolve_ids = {}
 			for id in thread_ids
 				resolve_ids[id] = true
@@ -231,7 +234,7 @@ define [
 					@_onCommentRemoved(comment)
 			@broadcastChange()
 			
-		unresolveCommentByThreadId: (thread_id) ->
+		showCommentByThreadId: (thread_id) ->
 			for comment in @rangesTracker?.comments or []
 				if comment.op.t == thread_id
 					@_onCommentAdded(comment)
@@ -421,23 +424,18 @@ define [
 			lines = @editor.getSession().getDocument().getAllLines()
 			return AceShareJsCodec.shareJsOffsetToAcePosition(offset, lines)
 		
-		_onChangesMoved: (changes) ->
-			# TODO: PERFORMANCE: Only run through the Ace lines once, and calculate all
-			# change positions as we go.
-			for change in changes
-				start = @_shareJsOffsetToAcePosition(change.op.p)
-				if change.op.i?
-					end = @_shareJsOffsetToAcePosition(change.op.p + change.op.i.length)
-				else
-					end = start
-				@_updateMarker(change.id, start, end)
-			@editor.renderer.updateBackMarkers()
+		_onChangeMoved: (change) ->
+			start = @_shareJsOffsetToAcePosition(change.op.p)
+			if change.op.i?
+				end = @_shareJsOffsetToAcePosition(change.op.p + change.op.i.length)
+			else
+				end = start
+			@_updateMarker(change.id, start, end)
 		
 		_onCommentMoved: (comment) ->
 			start = @_shareJsOffsetToAcePosition(comment.op.p)
 			end = @_shareJsOffsetToAcePosition(comment.op.p + comment.op.c.length)
 			@_updateMarker(comment.id, start, end)
-			@editor.renderer.updateBackMarkers()
 	
 		_updateMarker: (change_id, start, end) ->
 			return if !@changeIdToMarkerIdMap[change_id]?
diff --git a/services/web/public/coffee/ide/review-panel/RangesTracker.coffee b/services/web/public/coffee/ide/review-panel/RangesTracker.coffee
index 865ecf4ef6..1f32f19d3a 100644
--- a/services/web/public/coffee/ide/review-panel/RangesTracker.coffee
+++ b/services/web/public/coffee/ide/review-panel/RangesTracker.coffee
@@ -1,5 +1,5 @@
-load = (EventEmitter) ->
-	class RangesTracker extends EventEmitter
+load = () ->
+	class RangesTracker
 		# The purpose of this class is to track a set of inserts and deletes to a document, like
 		# track changes in Word. We store these as a set of ShareJs style ranges:
 		#   {i: "foo", p: 42} # Insert 'foo' at offset 42
@@ -36,6 +36,7 @@ load = (EventEmitter) ->
 		#     middle of a previous insert by the first user, the original insert will be split into two.
 		constructor: (@changes = [], @comments = []) ->
 			@setIdSeed(RangesTracker.generateIdSeed())
+			@resetDirtyState()
 
 		getIdSeed: () ->
 			return @id_seed
@@ -75,7 +76,7 @@ load = (EventEmitter) ->
 			comment = @getComment(comment_id)
 			return if !comment?
 			@comments = @comments.filter (c) -> c.id != comment_id
-			@emit "comment:removed", comment
+			@_markAsDirty comment, "comment", "removed"
 		
 		getChange: (change_id) ->
 			change = null
@@ -103,7 +104,11 @@ load = (EventEmitter) ->
 				@addComment(op, metadata)
 			else
 				throw new Error("unknown op type")
-			
+
+		applyOps: (ops, metadata = {}) ->
+			for op in ops
+				@applyOp(op, metadata)
+
 		addComment: (op, metadata) ->
 			# TODO: Don't allow overlapping comments?
 			@comments.push comment = {
@@ -114,18 +119,18 @@ load = (EventEmitter) ->
 					t: op.t
 				metadata
 			}
-			@emit "comment:added", comment
+			@_markAsDirty comment, "comment", "added"
 			return comment
 		
 		applyInsertToComments: (op) ->
 			for comment in @comments
 				if op.p <= comment.op.p
 					comment.op.p += op.i.length
-					@emit "comment:moved", comment
+					@_markAsDirty comment, "comment", "moved"
 				else if op.p < comment.op.p + comment.op.c.length
 					offset = op.p - comment.op.p
 					comment.op.c = comment.op.c[0..(offset-1)] + op.i + comment.op.c[offset...]
-					@emit "comment:moved", comment
+					@_markAsDirty comment, "comment", "moved"
 
 		applyDeleteToComments: (op) ->
 			op_start = op.p
@@ -138,7 +143,7 @@ load = (EventEmitter) ->
 				if op_end <= comment_start
 					# delete is fully before comment
 					comment.op.p -= op_length
-					@emit "comment:moved", comment
+					@_markAsDirty comment, "comment", "moved"
 				else if op_start >= comment_end
 					# delete is fully after comment, nothing to do
 				else
@@ -161,7 +166,7 @@ load = (EventEmitter) ->
 					
 					comment.op.p = Math.min(comment_start, op_start)
 					comment.op.c = remaining_before + remaining_after
-					@emit "comment:moved", comment
+					@_markAsDirty comment, "comment", "moved"
 
 		applyInsertToChanges: (op, metadata) ->
 			op_start = op.p
@@ -206,12 +211,12 @@ load = (EventEmitter) ->
 					# If this is an insert op at the end of an existing insert with a delete following, and it cancels out the following
 					# delete then we shouldn't append it to this insert, but instead only cancel the following delete.
 					# E.g.
-					#                   foo|<--- about to insert 'b' here
+					#                   foo|<--- about to insert 'bar' here
 					#  inserted 'foo'  --^ ^-- deleted 'bar'
-					# should become just 'foo' not 'foob' (with the delete marker becoming just 'ar'), .
+					# should become just 'foo' not 'foobar' (with the delete marker disappearing), .
 					next_change = @changes[i+1]
 					is_op_adjacent_to_next_delete = next_change? and next_change.op.d? and op.p == change_end and next_change.op.p == op.p
-					will_op_cancel_next_delete = is_op_adjacent_to_next_delete and next_change.op.d.slice(0, op.i.length) == op.i
+					will_op_cancel_next_delete = is_op_adjacent_to_next_delete and next_change.op.d == op.i
 					
 					# If there is a delete at the start of the insert, and we're inserting
 					# at the start, we SHOULDN'T merge since the delete acts as a partition.
@@ -281,8 +286,8 @@ load = (EventEmitter) ->
 			for change in remove_changes
 				@_removeChange change
 			
-			if moved_changes.length > 0
-				@emit "changes:moved", moved_changes
+			for change in moved_changes
+				@_markAsDirty change, "change", "moved"
 		
 		applyDeleteToChanges: (op, metadata) ->
 			op_start = op.p
@@ -406,8 +411,8 @@ load = (EventEmitter) ->
 					@_removeChange change
 					moved_changes = moved_changes.filter (c) -> c != change
 			
-			if moved_changes.length > 0
-				@emit "changes:moved", moved_changes
+			for change in moved_changes
+				@_markAsDirty change, "change", "moved"
 
 		_addOp: (op, metadata) ->
 			change = {
@@ -427,17 +432,11 @@ load = (EventEmitter) ->
 				else
 					return -1
 
-			if op.d?
-				@emit "delete:added", change
-			else if op.i?
-				@emit "insert:added", change
+			@_markAsDirty(change, "change", "added")
 		
 		_removeChange: (change) ->
 			@changes = @changes.filter (c) -> c.id != change.id
-			if change.op.d?
-				@emit "delete:removed", change
-			else if change.op.i?
-				@emit "insert:removed", change
+			@_markAsDirty change, "change", "removed"
 			
 		_applyOpModifications: (content, op_modifications) ->
 			# Put in descending position order, with deleting first if at the same offset 
@@ -486,13 +485,32 @@ load = (EventEmitter) ->
 					previous_change = change
 			return { moved_changes, remove_changes }
 		
+		resetDirtyState: () ->
+			@_dirtyState = {
+				comment: {
+					moved: {}
+					removed: {}
+					added: {}
+				}
+				change: {
+					moved: {}
+					removed: {}
+					added: {}
+				}
+			}
+		
+		getDirtyState: () ->
+			return @_dirtyState
+		
+		_markAsDirty: (object, type, action) ->
+			@_dirtyState[type][action][object.id] = object
+		
 		_clone: (object) ->
 			clone = {}
 			(clone[k] = v for k,v of object)
 			return clone
 
 if define?
-	define ["utils/EventEmitter"], load
+	define [], load
 else
-	EventEmitter = require("events").EventEmitter
-	module.exports = load(EventEmitter)
\ No newline at end of file
+	module.exports = load()
\ No newline at end of file