diff --git a/light9/rdfdb/rdflibpatch.py b/light9/rdfdb/rdflibpatch.py
--- a/light9/rdfdb/rdflibpatch.py
+++ b/light9/rdfdb/rdflibpatch.py
@@ -70,6 +70,7 @@ def graphFromQuads(q):
 
 def graphFromNQuad(text):
     g1 = ConjunctiveGraph()
+    # text might omit ctx on some lines. rdflib just puts in a bnode, which shows up later.
     g1.parse(data=text, format='nquads')
     return g1
 
diff --git a/light9/web/effects/effects.coffee b/light9/web/effects/effects.coffee
--- a/light9/web/effects/effects.coffee
+++ b/light9/web/effects/effects.coffee
@@ -4,7 +4,7 @@ Polymer
     graph: {type: Object}
     effectClasses: { type: Array }
   ready: ->
-    @graph.runHandler(@getClasses.bind(@))
+    @graph.runHandler(@getClasses.bind(@), 'getClasses')
 
   getClasses: ->
     U = (x) => @graph.Uri(x)
diff --git a/light9/web/graph.coffee b/light9/web/graph.coffee
--- a/light9/web/graph.coffee
+++ b/light9/web/graph.coffee
@@ -71,6 +71,9 @@ class AutoDependencies
   runHandler: (func, label) ->
     # what if we have this func already? duplicate is safe?
 
+    if not label?
+      throw new Error("missing label")
+
     h = new Handler(func, label)
     @handlerStack[@handlerStack.length - 1].innerHandlers.push(h)
     console.time("handler #{label}")
@@ -127,10 +130,10 @@ class window.SyncedGraph
     @clearGraph()
 
     if @patchSenderUrl
-      @_client = new RdfDbClient(@patchSenderUrl, @clearGraph.bind(@),
+      @_client = new RdfDbClient(@patchSenderUrl, @_clearGraphOnNewConnection.bind(@),
                                  @_applyPatch.bind(@), @setStatus)
     
-  clearGraph: -> # for debugging
+  clearGraph: ->
     # just deletes the statements; watchers are unaffected.
     if @graph?
       @_applyPatch({addQuads: [], delQuads: @graph.find()})
@@ -139,7 +142,11 @@ class window.SyncedGraph
     @graph = N3.Store()
     @_addPrefixes(@prefixes)
     @cachedFloatValues = new Map();
-    
+
+  _clearGraphOnNewConnection: -> # must not send a patch to the server!
+    log('graph: clearGraphOnNewConnection')
+    @clearGraph()
+    log('graph: clearGraphOnNewConnection done')
       
   _addPrefixes: (prefixes) ->
     @graph.addPrefixes(prefixes)
@@ -175,6 +182,13 @@ class window.SyncedGraph
   applyAndSendPatch: (patch) ->
     if !Array.isArray(patch.addQuads) || !Array.isArray(patch.delQuads)
       throw new Error("corrupt patch: #{patch}")
+
+    for qs in [patch.addQuads, patch.delQuads]
+      for q in qs
+        if not q.graph?
+          throw new Error("corrupt patch: #{q}")
+
+    log('graph: patch', patch)
     @_applyPatch(patch)
     @_client.sendPatch(patch) if @_client
 
diff --git a/light9/web/live/live.coffee b/light9/web/live/live.coffee
--- a/light9/web/live/live.coffee
+++ b/light9/web/live/live.coffee
@@ -157,7 +157,7 @@ Polymer
     @newEffectName = ''
 
   onGraph: ->
-    @graph.runHandler(@update.bind(@))
+    @graph.runHandler(@update.bind(@), 'controls')
   resendAll: ->
     for llc in @getElementsByTagName("light9-live-control")
       llc.resend()
diff --git a/light9/web/rdfdbclient.coffee b/light9/web/rdfdbclient.coffee
--- a/light9/web/rdfdbclient.coffee
+++ b/light9/web/rdfdbclient.coffee
@@ -52,7 +52,7 @@ parseJsonPatch = (jsonPatch, cb) ->
 
 class window.RdfDbClient
   # Send and receive patches from rdfdb
-  constructor: (@patchSenderUrl, @clearGraph, @applyPatch, @setStatus) ->
+  constructor: (@patchSenderUrl, @clearGraphOnNewConnection, @applyPatch, @setStatus) ->
     @_patchesToSend = []
     @_lastPingMs = -1
     @_patchesReceived = 0
@@ -77,7 +77,7 @@ class window.RdfDbClient
       #{ping}ms")
  
   sendPatch: (patch) ->
-    console.log('queue patch to server ', patchSizeSummary(patch))
+    console.log('rdfdbclient: queue patch to server ', patchSizeSummary(patch))
     @_patchesToSend.push(patch)
     @_updateStatus()
     @_continueSending()           
@@ -89,17 +89,17 @@ class window.RdfDbClient
     @ws = new WebSocket(fullUrl)
 
     @ws.onopen = =>
-      log('connected to', fullUrl)
+      log('rdfdbclient: connected to', fullUrl)
       @_updateStatus()
-      @clearGraph()
+      @clearGraphOnNewConnection()
       @_pingLoop()
 
     @ws.onerror = (e) =>
-      log('ws error ' + e)
+      log('rdfdbclient: ws error ' + e)
       @ws.onclose()
 
     @ws.onclose = =>
-      log('ws close')
+      log('rdfdbclient: ws close')
       @_updateStatus()
       clearTimeout(@_reconnectionTimeout) if @_reconnectionTimeout?
       @_reconnectionTimeout = setTimeout(@_newConnection.bind(@), 1000)
@@ -134,7 +134,7 @@ class window.RdfDbClient
 
     sendOne = (patch, cb) =>
         toJsonPatch(patch, (json) =>
-          log('send patch to server, ' + json.length + ' bytes')
+          log('rdfdbclient: send patch to server, ' + json.length + ' bytes')
           @ws.send(json)
           @_patchesSent++
           @_updateStatus()
diff --git a/light9/web/timeline/timeline.coffee b/light9/web/timeline/timeline.coffee
--- a/light9/web/timeline/timeline.coffee
+++ b/light9/web/timeline/timeline.coffee
@@ -285,7 +285,7 @@ Polymer
     song: { type: String, notify: true }
     zoomInX: { type: Object, notify: true }
     rows: { value: [0...ROW_COUNT] }
-    zoom: { type: Object, notify: true, observer: 'onZoom' }
+    zoom: { type: Object, notify: true, observer: 'onZoom' } # viewState.zoomSpec
     zoomFlattened: { type: Object, notify: true }
   onZoom: ->
     updateZoomFlattened = ->
@@ -364,6 +364,7 @@ Polymer
 
     desiredWidthX = @offsetWidth * .3
     desiredWidthT = @zoomInX.invert(desiredWidthX) - @zoomInX.invert(0)
+    desiredWidthT = Math.min(desiredWidthT, @zoom.duration() - dropTime)
     
     for i in [0...4]
       pt = points[i]
@@ -630,6 +631,9 @@ Polymer
 
   editAttr: (song, note, attr, value) ->
     U = (x) => @graph.Uri(x)
+    if not song?
+      log("can't edit inline attr yet, no song")
+      return
     quad = (s, p, o) => {subject: s, predicate: p, object: o, graph: song}
 
     existingColorScaleSetting = null
@@ -650,7 +654,7 @@ Polymer
       @graph.applyAndSendPatch(patch)
     
   addHandler: ->
-    @graph.runHandler(@update.bind(@))
+    @graph.runHandler(@update.bind(@), "update inline attrs #{@uri}")
     
   update: ->
     #console.time('attrs update')