Fixed #2651: indicate better that sample code is locked when it won't let them type in there.

app/styles/play/level/tome/spell.sass

@@ -175,6 +175,22 @@
 
       .locked-code
         border: 1px dashed rgba(53, 45, 34, 0.5)
+        background-color: transparent
+        @include transition(background-color 0.25s ease-in-out)
+
+        &:after
+          content: "Locked"
+          opacity: 0
+          display: block
+          text-align: right
+          @include transition(opacity 4s ease-in-out)
+          font-size: 24px
+
+        &.pulsating
+          background-color: rgba(53, 45, 34, 0.5)
+
+          &:after
+            opacity: 1
 
     // Decided it wasn't useful to show what can be hovered, since almost anything can, so we have to make it too faint to be useful if we don't want it to be really distracting.
     //.ace_identifier

app/views/play/level/tome/SpellView.coffee

@@ -295,8 +295,13 @@ module.exports = class SpellView extends CocoView
       return true for range in @readOnlyRanges when rightRange.intersects(range)
       false
 
+    pulseLockedCode = ->
+      $('.locked-code').finish().addClass('pulsating').effect('shake', times: 1, distance: 2, direction: 'down').removeClass('pulsating')
+
     preventReadonly = (next) ->
-      return true if intersects()
+      if intersects()
+        pulseLockedCode()
+        return true
       next?()
 
     interceptCommand = (obj, method, wrapper) ->
@@ -359,16 +364,13 @@ module.exports = class SpellView extends CocoView
     @ace.commands.on 'exec', (e) =>
       e.stopPropagation()
       e.preventDefault()
-      if e.command.name is 'insertstring'and intersects()
+      if (e.command.name is 'insertstring' and intersects()) or
+         (e.command.name in ['Backspace', 'throttle-backspaces'] and intersectsLeft()) or
+         (e.command.name is 'del' and intersectsRight())
         @zatanna?.off?()
+        pulseLockedCode()
         return false
-      if e.command.name in ['Backspace', 'throttle-backspaces'] and intersectsLeft()
-        @zatanna?.off?()
-        return false
-      if e.command.name is 'del' and intersectsRight()
-        @zatanna?.off?()
-        return false
-      if e.command.name in ['enter-skip-delimiters', 'Enter', 'Return']
+      else if e.command.name in ['enter-skip-delimiters', 'Enter', 'Return']
         if intersects()
           e.editor.navigateDown 1
           e.editor.navigateLineStart()