Prevent close button from causing a page reload

This was effectively closing all tabs via a page reload.  The page
load is just fast enough it looked like the tabs were all closing.
Fix alerts to the top of the page

Previously the alerts were not visibile if you were below the fold.
Add a litte space around the alerts.
Make the editor handle it's own scrolling

It was getting sorta weird when you reached the bottom of the page,
sometimes the cursor being below the fold, and was jumpy in resizing.
This might not work very well at different resolutions, need to test
that more.