diff --git a/.eslintrc b/.eslintrc
index 093ed358b6f..9404630b5bc 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -22,7 +22,6 @@
     "no-trailing-spaces": [2],
     "no-multiple-empty-lines": [2, {"max": 2, "maxEOF": 0}],
     "eol-last": [2],
-    "linebreak-style": [2, "unix"],
     "indent": [2, 4, {"SwitchCase": 1}],
     "max-len": [0, 80],
     "brace-style": [0, "stroustrup", {"allowSingleLine": true}],
diff --git a/src/plot_api/plot_api.js b/src/plot_api/plot_api.js
index bd9f22f8fe8..11191a1d275 100644
--- a/src/plot_api/plot_api.js
+++ b/src/plot_api/plot_api.js
@@ -956,6 +956,12 @@ Plotly.addTraces = function addTraces(gd, traces, newIndices) {
     if(!Array.isArray(traces)) {
         traces = [traces];
     }
+
+    // make sure traces do not repeat existing ones
+    traces = traces.map(function(trace) {
+        return Lib.extendFlat({}, trace);
+    });
+
     helpers.cleanData(traces, gd.data);
 
     // add the traces to gd.data (no redrawing yet!)