There's a bug in El Capitan when trying to install SASS. A quick workaround exists, however.
As someone who uses OS X dashboard widgets often, I was dismayed to find out that Apple has hidden it by default. Thankfully, it's easy to reenable the dashboard in El Capitan. Here's how to do it.
A new (but annoying) feature in El Capitan is to enlarge the cursor substantially when you shake the mouse, or when you move it too quickly.