fix(removeSelected): fix incorrect removal of preselected item

Ensure that `removeSelected` only affects `multiple`s, include unit test, and add comment in demo examples.

Closes #1672

Author: dondi

Diff for: docs/assets/demo.js

@@ -150,6 +150,8 @@ app.controller('DemoCtrl', function ($scope, $http, $timeout, $interval) {
   vm.person.selectedValue = vm.peopleObj[3];
   vm.person.selectedSingle = 'Samantha';
   vm.person.selectedSingleKey = '5';
+  // To run the demos with a preselected person object, uncomment the line below.
+  //vm.person.selected = vm.person.selectedValue;
 
   vm.people = [
     { name: 'Adam',      email: '[email protected]',      age: 12, country: 'United States' },

Diff for: src/uiSelectController.js

@@ -235,7 +235,7 @@ uis.controller('uiSelectCtrl',
       data = data || ctrl.parserResult.source($scope);
       var selectedItems = ctrl.selected;
       //TODO should implement for single mode removeSelected
-      if (ctrl.isEmpty() || (angular.isArray(selectedItems) && !selectedItems.length) || !ctrl.removeSelected) {
+      if (ctrl.isEmpty() || (angular.isArray(selectedItems) && !selectedItems.length) || !ctrl.multiple || !ctrl.removeSelected) {
         ctrl.setItemsFn(data);
       }else{
         if ( data !== undefined && data !== null ) {

Diff for: test/select.spec.js

@@ -1427,7 +1427,7 @@ describe('ui-select tests', function() {
     expect($(el).scope().$select.selected).toEqual(['idontexist']);
   });
 
-  it('should remove a choice when remove-selected is not given (default is true)', function () {
+  it('should remove a choice when multiple and remove-selected is not given (default is true)', function () {
 
     var el = compileTemplate(
       '<ui-select multiple ng-model="selection.selected"> \
@@ -1453,6 +1453,31 @@ describe('ui-select tests', function() {
     });
   });
 
+  it('should not remove a pre-selected choice when not multiple and remove-selected is not given (default is true)', function () {
+    scope.selection.selected = scope.people[5]; // Samantha
+
+    var el = compileTemplate(
+      '<ui-select ng-model="selection.selected"> \
+        <ui-select-match placeholder="Pick one...">{{$select.selected.name}}</ui-select-match> \
+        <ui-select-choices repeat="person in people | filter: $select.search"> \
+          <div class="person-name" ng-bind-html="person.name" | highlight: $select.search"></div> \
+          <div ng-bind-html="person.email | highlight: $select.search"></div> \
+        </ui-select-choices> \
+      </ui-select>'
+    );
+
+    expect(getMatchLabel(el)).toEqual("Samantha");
+    openDropdown(el);
+
+    var choicesEls = $(el).find('.ui-select-choices-row');
+    expect(choicesEls.length).toEqual(8);
+
+    ['Adam', 'Amalie', 'Estefanía', 'Adrian', 'Wladimir', 'Samantha', 'Nicole', 'Natasha'].forEach(function (name, index) {
+      expect($(choicesEls[index]).hasClass('disabled')).toBeFalsy();
+      expect($(choicesEls[index]).find('.person-name').text()).toEqual(name);
+    });
+  });
+
   it('should disable a choice instead of removing it when remove-selected is false', function () {
 
     var el = compileTemplate(