diff --git a/js/lib/d3.combobox.js b/js/lib/d3.combobox.js
index 174d08c9c..bd8482f80 100644
--- a/js/lib/d3.combobox.js
+++ b/js/lib/d3.combobox.js
@@ -187,7 +187,7 @@ d3.combobox = function() {
 
             for (var i = 0; i < suggestions.length; i++) {
                 if (suggestions[i].value.toLowerCase().indexOf(v.toLowerCase()) === 0) {
-                    var completion = v + suggestions[i].value.substr(v.length);
+                    var completion = suggestions[i].value;
                     idx = i;
                     input.property('value', completion);
                     input.node().setSelectionRange(v.length, completion.length);
diff --git a/test/spec/lib/d3.combobox.js b/test/spec/lib/d3.combobox.js
index a0fa5d66c..9304f735e 100644
--- a/test/spec/lib/d3.combobox.js
+++ b/test/spec/lib/d3.combobox.js
@@ -132,11 +132,11 @@ describe("d3.combobox", function() {
         expect(input.property('selectionEnd')).to.equal(3);
     });
 
-    it("preserves the case of the input portion of the value", function() {
+    it("does not preserve the case of the input portion of the value", function() {
         input.call(combobox.data(data));
         input.node().focus();
         simulateKeypress('B');
-        expect(input.property('value')).to.equal('Bar');
+        expect(input.property('value')).to.equal('bar');
         expect(input.property('selectionStart')).to.equal(1);
         expect(input.property('selectionEnd')).to.equal(3);
     });