Start by restoring your InDesign preferences:
It would also help if you told us your InDesign version and what operating system you're running.
Hello Steve Werner,
have the same problem. The font list is, but is empty.
I have Mac OS X 10.11.5 El Capitan. CPU i7 3.5GHz 32GB RAM
Adobe InDesign CS6 version v8.1.
Can you help me?
InDesign CS6 is not supported under El Capitan, you should either roll back your OS or upgrade to InDesign CC2015.
As Derek says, CS6 is not supported on 10.11, there are many reports of various glitches and the best advice is to upgrade your Adobe product.
However, for font issues, try to substantially reduce the number of fonts you use at any one time and check font health by validating them with Font Book. Don't use any suspect fonts.
For panel problems try advice here Wonky Panel Behavior
and elsewhere in these forums.
Allen best thanks. I did downgrade to OS X 10.10.5.