Sharepoint Three State Workflow is Disabled

There is a section for WORKFLOW STATES with DROPDOWN menus for this:
- Choice field
- Initial State
- Middle State
- Final State



Problem: This is disabled.

I'm not sure if this is the best solution but I tried this and it worked:
- Create a column on your document library.


- Select column type to Choice (menu to choose from)
- Supply the choices and other information.
- Click OK if done.



Now go on to your workflow settings and check WORKFLOW STATES section should be enabled right now. The choices you have entered previously would appear on these states.



Hope it'd help. :P

Check this post too.