--- a/light9/live/Effect.ts	Mon May 29 13:24:01 2023 -0700
+++ b/light9/live/Effect.ts	Mon May 29 13:58:04 2023 -0700
@@ -93,7 +93,7 @@
       newSettings.push({ device, deviceAttr, setting, value });
     }
     this.settings = newSettings;
-    log(`rebuild to ${this.settings.length}`);
+    log(`settings is rebuilt to length ${this.settings.length}`);
     this.settingsChanged.emit(); // maybe one emitter per dev+attr?
     // this.onValuesChanged();
   }

--- a/light9/live/Light9AttrControl.ts	Mon May 29 13:24:01 2023 -0700
+++ b/light9/live/Light9AttrControl.ts	Mon May 29 13:58:04 2023 -0700
@@ -93,17 +93,31 @@
 
   private onValueProperty() {
     if (this.deviceAttrRow === null) throw new Error();
-    if (this.effect !== null && this.graph !== undefined) {
-      const p = this.effect.edit(this.deviceAttrRow.device, this.deviceAttrRow.uri, this.value);
-      if (p.adds.length || p.dels.length) {
-        log("Effect told us to graph.patch", p, "to", this.graph);
+    if (!this.graph) {
+      log('ignoring value change- no graph yet')
+      return;
+    }
+    if (this.effect === null) {
+      this.value = null;
+    } else {
+      const p = this.effect.edit(
+        //
+        this.deviceAttrRow.device,
+        this.deviceAttrRow.uri,
+        this.value
+      );
+      if (!p.isEmpty()) {
+        log("Effect told us to graph.patch this:\n", p.dump());
         this.graph.applyAndSendPatch(p);
       }
     }
   }
 
   private onEffectProperty() {
-    if (this.effect === null) throw new Error();
+    if (this.effect === null) {
+      log('no effect obj yet')
+      return;
+    }
     // effect will read graph changes on its own, but emit an event when it does
     this.effect.settingsChanged.subscribe(() => {
       this.effectSettingsChanged();

--- a/light9/web/SyncedGraph.ts	Mon May 29 13:24:01 2023 -0700
+++ b/light9/web/SyncedGraph.ts	Mon May 29 13:58:04 2023 -0700
@@ -153,9 +153,11 @@
       log("not connected-- dropping patch");
       return;
     }
+    if (patch.isEmpty()) throw 'should not get to this point with empty patch'
 
     this._applyPatch(patch);
     if (this.client) {
+      log("sending patch:\n", patch.dump())
       this.client.sendPatch(patch);
     }
     console.timeEnd("applyAndSendPatch");
@@ -165,7 +167,7 @@
     // In most cases you want applyAndSendPatch.
     //
     // This is the only method that writes to this.graph!
-    log("patch from server [1]");
+    log("_applyPatch [1]\n", patch.dump());
     this.cachedFloatValues.clear();
     this.cachedUriValues.clear();
     patch.applyToGraph(this.graph);

--- a/light9/web/patch.ts	Mon May 29 13:24:01 2023 -0700
+++ b/light9/web/patch.ts	Mon May 29 13:58:04 2023 -0700
@@ -52,6 +52,7 @@
   }
 
   isEmpty() {
+    // sometimes returns bogus false- waiting for port to Immutable
     return !this.dels.length && !this.adds.length;
   }
 
@@ -76,17 +77,20 @@
   dump(): string {
     const lines: string[] = [];
     const s = (term: N3.Term): string => {
-      if (term.termType=='Literal') return term.value;
-      if (term.termType=='NamedNode') return term.value
-        .replace("http://light9.bigasterisk.com/effect/","effect:")
-        .replace("http://light9.bigasterisk.com/",":")
-        .replace("http://www.w3.org/2000/01/rdf-schema#","rdfs:")
-        .replace("http://www.w3.org/1999/02/22-rdf-syntax-ns#", "rdf:")
-      if (term.termType=='BlankNode') return '_:'+term.value;
+      if (term.termType == "Literal") return term.value;
+      if (term.termType == "NamedNode")
+        return term.value
+          .replace("http://light9.bigasterisk.com/effect/", "effect:")
+          .replace("http://light9.bigasterisk.com/", ":")
+          .replace("http://www.w3.org/2000/01/rdf-schema#", "rdfs:")
+          .replace("http://www.w3.org/1999/02/22-rdf-syntax-ns#", "rdf:");
+      if (term.termType == "BlankNode") return "_:" + term.value;
       return term.id;
     };
-    this.dels.forEach((d) => lines.push("- " + s(d.subject) + " " + s(d.predicate) + " " + s(d.object)));
-    this.adds.forEach((d) => lines.push("+ " + s(d.subject) + " " + s(d.predicate) + " " + s(d.object)));
+    const delPrefix = "- ",
+      addPrefix = "\u200B+ "; // dels to sort before adds
+    this.dels.forEach((d) => lines.push(delPrefix + s(d.subject) + " " + s(d.predicate) + " " + s(d.object)));
+    this.adds.forEach((d) => lines.push(addPrefix + s(d.subject) + " " + s(d.predicate) + " " + s(d.object)));
     lines.sort();
     return lines.join("\n");
   }