Fix selecting then Tabbing away and back then selecting

Steps to repro:
1. select stuff
2. while there's a selection, Tab away and back
3. at this point the math field should be focused and have a blinking
   cursor and no selection. Do Shift-Left or Shift-Right

The resulting selection will be quite wrong. This is because the
anticursor used is from the selection that was cleared when Tabbing
away.

src/services/focusBlur.js

@@ -18,7 +18,7 @@ Controller.open(function(_) {
       ctrlr.blurred = true;
       blurTimeout = setTimeout(function() { // wait for blur on window; if
         root.postOrder('intentionalBlur'); // none, intentional blur: #264
-        cursor.clearSelection();
+        cursor.clearSelection().endSelection();
         blur();
       });
       $(window).on('blur', windowBlur);

test/unit/focusBlur.test.js

@@ -1,4 +1,8 @@
 suite('focusBlur', function() {
+  function assertHasFocus(mq, name, invert) {
+    assert.ok(!!invert ^ $(mq.el()).find('textarea').is(':focus'), name + (invert ? ' does not have focus' : ' has focus'));
+  }
+
   suite('handlers can shift focus away', function() {
     var mq, mq2, wasUpOutOfCalled;
     setup(function() {
@@ -21,9 +25,6 @@ suite('focusBlur', function() {
       $(mq.el()).find('textarea').trigger(jQuery.Event('keydown', { which: 38 }));
       assert.ok(wasUpOutOfCalled);
     }
-    function assertHasFocus(mq, name) {
-      assert.ok($(mq.el()).find('textarea').is(':focus'), name + ' has focus');
-    }
 
     test('normally', function() {
       mq.focus();
@@ -50,4 +51,36 @@ suite('focusBlur', function() {
       });
     });
   });
+
+  test('select behaves normally after blurring and re-focusing', function(done) {
+    var mq = MQ.MathField($('<span></span>').appendTo('#mock')[0]);
+
+    mq.focus();
+    assertHasFocus(mq, 'mq');
+
+    mq.typedText('asdf');
+    assert.equal(mq.latex(), 'asdf');
+
+    mq.keystroke('Shift-Left');
+    setTimeout(function() {
+      assert.equal($(mq.el()).find('textarea').val(), 'f');
+
+      mq.blur();
+      assertHasFocus(mq, 'mq', 'not');
+      setTimeout(function() {
+        assert.equal($(mq.el()).find('textarea').val(), '');
+
+        mq.focus();
+        assertHasFocus(mq, 'mq');
+
+        mq.keystroke('Shift-Left');
+        setTimeout(function() {
+          assert.equal($(mq.el()).find('textarea').val(), 'd');
+
+          $(mq.el()).remove();
+          done();
+        });
+      }, 10);
+    });
+  });
 });