diff --git a/bumblebee/input.py b/bumblebee/input.py
index ba41362..7dea7d2 100644
--- a/bumblebee/input.py
+++ b/bumblebee/input.py
@@ -27,6 +27,8 @@ def read_input(inp):
         inp.has_event = True
         try:
             event = json.loads(line)
+            if not "instance" in event:
+                continue
             inp.callback(event)
             inp.redraw()
         except ValueError:
diff --git a/tests/test_i3barinput.py b/tests/test_i3barinput.py
index e2758d6..abe972f 100644
--- a/tests/test_i3barinput.py
+++ b/tests/test_i3barinput.py
@@ -47,7 +47,20 @@ class TestI3BarInput(unittest.TestCase):
         mock_input.readline.return_value = json.dumps({
             "name": None,
             "instance": None,
-            "button": None,
+            "button": 1,
+        })
+        self.input.start()
+        self.assertEquals(self.input.alive(), True)
+        self.assertEquals(self.input.stop(), True)
+        mock_input.readline.assert_any_call()
+
+    @mock.patch("select.select")
+    @mock.patch("sys.stdin")
+    def test_ignore_partial_event(self, mock_input, mock_select):
+        mock_select.return_value = (1,2,3)
+        self.input.register_callback(None, button=1, cmd=self.callback)
+        mock_input.readline.return_value = json.dumps({
+            "button": 1,
         })
         self.input.start()
         self.assertEquals(self.input.alive(), True)