Add portlet to layout fails at times

[cbeach47]

Describe the bug Adding a portlet to the layout via the customize drawer fails at times

To Reproduce Steps to reproduce the behavior:

1. Login as staff
2. On the Welcome tab, open the customize drawer and add the 'About.com' portlet
3. Note the screen does not refresh, and there is an error in the browser console (403 - {"error":"Unable to add element"} )
4. Switch to the Main Staff Tab
5. Retry adding the portlet to the layout
6. Note this time it succeeds

Expected behavior If there is a portlet that has an Add decorator on it, then it should be able to be added to the tab layout.

Screenshots

Stacktrace No stracktraces are produced

Platform:

• uPortal Version: 5.9.0 (issues in 5.8.2 as well)
• uPortal start: https://github.com/Jasig/uPortal-start/commit/0b1564ef94debcaa2e1f667ccbd73e4683ffaf67
• OS: Ubuntu
• Browser: Firefox