I am assuming you tried the following steps. Correct me if I am wrong.
1. Navigate to File->New Fluid Grid layout
2. Change the number of Grids for desktop to 10
3. Clicked on Create
4. Clicked "Save" on the Save Style Sheet File As dialog
If you are on a new site and this is the first time you are creating a Fluid Grid page, you will be prompted to save "boilerplate.css" and "respond.min.js". These files must be in your site to have the Fluid grid options enabled.
And yes the background is blue and not green. I am assuming you are seeing a dark blue border around the div and not the FG options correct?
If that is the case, can you try these?
-> Click on the div and see if the options are enabled?
-> Save the Fluid Grid file or do a "Save all"
If you are still unable to see the Fluid Grid options do send us a screenshot with the detailed steps. Also please make sure that the doctype chosen is not "None"
Thanks in advance,
Nithya