Description of problem:

I followed the instructions in the "Customizing your dynamic homepage to optimize your workflow" section. In RHDH, I clicked on the "Edit" button and noticed a couple of things:

1. There's no cancel button. In order to exit without changes, you have to hit "Save" or "Restore defaults" which does not make sense if you want to change your mind
2. Add widget shows the list of widgets that are already displayed. Adding them again would result in duplicate widgets.

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

1. On Home page, click "Edit"
2. No "cancel" button to exit out
3. Click "Add widget" and note that some of the widgets are already added

Actual results:

See above.

Expected results:

1. There should be a cancel or exit button
2. Only widgets that are not added to the homepage should be available options under "Add widget"

Reproducibility (Always/Intermittent/Only Once):

Always

Build Details:

1.8

Additional info (Such as Logs, Screenshots, etc):