Update README.md

README.md

@@ -94,13 +94,14 @@ The only required property for the component is `isOpen`, which controls whether
 | `width` | `string` | `300px` | The width of OffCanvas. | 
 | `height` | `string` | `300px` | The height of OffCanvas. |
 | `position` | `string` | `left` | Position OffCanvas to the `left`, `right`, `top` or `bottom`. |
+| `mainContainerSelector` | `string` | | Allow `OffCanvas` to push your page. Pass a valid CSS selector of an element that should be pushed. |
 | `onClose` | `func` | | Callback fired when the overlay is clicked or esc key is pressed. |
 | `closeOnEsc` | `bool` | `true` | Close OffCanvas on esc key. |
 | `closeOnOverlayClick` | `bool` | `true` | Close OffCanvas on overlay click. | 
 | `trapFocusAfterOpen` | `bool` | `true` | Trap focus when OffCanvas is open. |
 | `returnFocusAfterClose` | `bool` | `true` | Return focus to the element that had focus before opening OffCanvas. |
 | `focusFirstChildAfterOpen` | `bool` | | Set initial focus on the first focusable child inside OffCanvas. |
-| `focusThisChildAfterOpen` | `string` | | Set initial focus on a specific child inside OffCanvas. The `string` must be a valid CSS selector, because it is passed to `document.querySelector()`.
+| `focusThisChildAfterOpen` | `string` | | Set initial focus on a specific child inside OffCanvas. Pass a valid CSS selector of an element that should receive initial focus.
 | `style` | `object` | `{ overlay: {}, content: {} }` | Inline styles object. It has two keys: `overlay` - overlay styles and `content` - OffCanvas styles. |
 | `className` | `string` | | Custom className for OffCanvas. |
 | `overlayClassName` | `string` | | Custom className for the overlay. |