How To Lock/Unlock Elements
Sometimes it's handy to Lock an element(s) on the canvas. This really helps when working with large images (such as using an image as a custom background).
To Lock any element on the canvas, simply right click your mouse on the element (icon, shape, text. image) and select "Lock" (or use Ctrl + L) as shown here:
Next, you will see a "Lock" symbol beside the element to indicate that this element is Locked.
To remove this Lock, right-click on the element and select Unlock as shown here:
Now you can move this element around the canvas since it is unlocked.