diff --git a/lib/mixins/canvas-drawer.coffee b/lib/mixins/canvas-drawer.coffee
index e9bd2192..80226672 100644
--- a/lib/mixins/canvas-drawer.coffee
+++ b/lib/mixins/canvas-drawer.coffee
@@ -423,9 +423,6 @@ class CanvasDrawer extends Mixin
     for change in @pendingChanges
       newIntactRanges = []
       for range in intactRanges
-        if isNaN(change.screenDelta)
-          change.screenDelta = change.end - change.start
-
         if change.end < range.start and change.screenDelta != 0
           newIntactRanges.push(
             start: range.start + change.screenDelta
diff --git a/lib/mixins/decoration-management.coffee b/lib/mixins/decoration-management.coffee
index eb767bc0..8c814c3a 100644
--- a/lib/mixins/decoration-management.coffee
+++ b/lib/mixins/decoration-management.coffee
@@ -198,7 +198,7 @@ class DecorationManagement extends Mixin
 
       [start, end] = [end, start] if start.row > end.row
 
-      @emitRangeChanges({start, end, screenDelta: end - start})
+      @emitRangeChanges({start, end})
 
     decoration = new Decoration(marker, this, decorationParams)
     @decorationsByMarkerId[marker.id] ?= []
@@ -229,14 +229,12 @@ class DecorationManagement extends Mixin
   # Internal: Emits a change for the specified range.
   #
   # range - The `Range` to emits changes for.
-  emitRangeChanges: (range) ->
+  emitRangeChanges: (range, screenDelta) ->
     startScreenRow = range.start.row
     endScreenRow = range.end.row
     lastRenderedScreenRow  = @getLastVisibleScreenRow()
     firstRenderedScreenRow = @getFirstVisibleScreenRow()
-    screenDelta = (lastRenderedScreenRow - firstRenderedScreenRow) - (endScreenRow - startScreenRow)
-
-    screenDelta = 0 if isNaN(screenDelta)
+    screenDelta ?= (lastRenderedScreenRow - firstRenderedScreenRow) - (endScreenRow - startScreenRow)
 
     changeEvent =
       start: startScreenRow