Fix calendar opening when clicking inside the wrapper

src/DateInput.jsx

@@ -347,9 +347,13 @@ export default class DateInput extends PureComponent {
   }
 
   onClick = (event) => {
-    if (event.target === event.currentTarget) {
+    if (
+      event.target !== this.dayInput.current &&
+      event.target !== this.monthInput.current &&
+      event.target !== this.yearInput.current
+    ) {
       // Wrapper was directly clicked
-      const firstInput = event.target.children[1];
+      const firstInput = event.currentTarget.querySelector('input[data-input]');
       focus(firstInput);
     }
   };

src/DatePicker.spec.jsx

@@ -499,4 +499,38 @@ describe('DatePicker', () => {
 
     expect(onChange).toHaveBeenCalledWith(null);
   });
+
+  it('focuses on first custom input when clicking on divider', () => {
+    const date = new Date(2017, 8, 30);
+    let customInput;
+    let divider;
+
+    const { container, rerender } = render(<DatePicker />);
+
+    customInput = container.querySelector('input[data-input]');
+    divider = container.querySelector('.react-date-picker__inputGroup__divider');
+
+    fireEvent.click(divider);
+    expect(customInput).toHaveFocus();
+
+    rerender(<DatePicker value={date} />);
+
+    customInput = container.querySelector('input[data-input]');
+    divider = container.querySelector('.react-date-picker__inputGroup__divider');
+
+    fireEvent.click(divider);
+    expect(customInput).toHaveFocus();
+  });
+
+  it('focuses on first custom input when clicking on leading zero', () => {
+    const date = new Date(2017, 8, 30);
+
+    const { container } = render(<DatePicker showLeadingZeros value={date} />);
+
+    const customInput = container.querySelector('input[data-input]');
+    const leadingZero = container.querySelector('.react-date-picker__inputGroup__leadingZero');
+
+    fireEvent.click(leadingZero);
+    expect(customInput).toHaveFocus();
+  });
 });