Merge branch '4.0'

 # Conflicts:
 #	client/dist/js/bundle.js

.travis.yml

@@ -26,7 +26,7 @@ matrix:
     - php: 7.2
       env: DB=MYSQL RECIPE_VERSION=4.x-dev PHPUNIT_TEST=1
     - php: 7.2
-      env: DB=MYSQL RECIPE_VERSION=4.x-dev NPM_TEST=1
+      env: DB=MYSQL RECIPE_VERSION=4.3.x-dev NPM_TEST=1
 
 before_script:
   # Extra $PATH

client/src/components/ElementEditor/AddNewButton.js

@@ -31,7 +31,8 @@ class AddNewButton extends Component {
     const buttonAttributes = {
       id: `ElementalArea${elementalAreaId}_AddButton`,
       color: 'primary',
-      onClick: this.toggle
+      onClick: this.toggle,
+      className: 'font-icon-plus',
     };
 
     return (

client/src/components/TextCheckboxGroupField/TextCheckboxGroupField.js

@@ -3,21 +3,27 @@ import { InputGroup, InputGroupAddon, InputGroupText } from 'reactstrap';
 import fieldHolder from 'components/FieldHolder/FieldHolder';
 
 const TextCheckboxGroupField = (props) => {
-    const { children } = props;
+  const { children } = props;
 
-    const childrenWithProps = React.Children.toArray(
-      React.Children.map(children, child =>
-        React.cloneElement(child, { noHolder: true })
-      )
-    );
-    return (
-      <InputGroup className="text-checkout-group-field">
-        {childrenWithProps[0]}
-        <InputGroupAddon addonType="append">
-          <InputGroupText>{childrenWithProps[1]}</InputGroupText>
-        </InputGroupAddon>
-      </InputGroup>
-    );
+  const childrenWithProps = React.Children.toArray(
+    React.Children.map(children, child =>
+      React.cloneElement(child, { noHolder: true })
+    )
+  );
+
+  // If the checkbox has been removed, just render the TextField on its own
+  if (childrenWithProps.length === 1) {
+    return childrenWithProps[0];
+  }
+
+  return (
+    <InputGroup className="text-checkout-group-field">
+      {childrenWithProps[0]}
+      <InputGroupAddon addonType="append">
+        <InputGroupText>{childrenWithProps[1]}</InputGroupText>
+      </InputGroupAddon>
+    </InputGroup>
+  );
 };
 
 export default fieldHolder(TextCheckboxGroupField);

src/Forms/ElementalAreaField.php

@@ -229,6 +229,10 @@ public function saveInto(DataObjectInterface $dataObject)
         $elementData = $this->Value();
         $idPrefixLength = strlen(sprintf(ElementalAreaController::FORM_NAME_TEMPLATE, ''));
 
+        if (!$elementData) {
+            return;
+        }
+
         foreach ($elementData as $form => $data) {
             // Extract the ID
             $elementId = (int) substr($form, $idPrefixLength);

tests/BaseElementTest.php

@@ -175,4 +175,26 @@ public function testEvenOdd()
         $this->assertEquals('even', $element2->EvenOdd());
         $this->assertEquals('odd', $element3->EvenOdd());
     }
+
+    public function testOnBeforeWrite()
+    {
+        /** @var ElementalArea $area */
+        $area = $this->objFromFixture(ElementalArea::class, 'area51');
+
+        $element1 = new ElementContent();
+        $element1->ParentID = $area->ID;
+        $element1->write();
+        $baselineSort = $element1->Sort;
+
+        $element2 = new ElementContent();
+        $element2->ParentID = $area->ID;
+        $element2->write();
+        $this->assertEquals($baselineSort + 1, $element2->Sort, 'Sort order should be higher than the max');
+
+        // Use a different element type, ensuring that sort orders are relative to the BaseElement
+        $element3 = new TestElement();
+        $element3->ParentID = $area->ID;
+        $element3->write();
+        $this->assertEquals($baselineSort + 2, $element3->Sort, 'Sort order should be higher than the max');
+    }
 }