What you report is consistent with a paused script. Is there, by any chance, a script set to run OnFirstWindow open that might be paused at this point?
There are no scripts paused when I run into this issue.
does this issue persist if you click [Enter] and/or [Esc] key several times?
No, hitting escape/enter does not fix the issue
Some things to check:
* switching to layout mode - still greyed-out?
* switching back to browse mode - still greyed-out?
* can you access the greyed-out layout by Manage Layouts window
Does this only happen in one specific file or do you see this in other files?
If one specific file, try recovering the file and then test the recovered copy to see if you get the same results.