operator panel is greyed out

I am having a problem. At the bottom of my tool shelf panel is the operator panel (where you would select the number of vertices in a circle, etc). For some reason it is greyed out. All the values are there for the newly created object, but they can’t be changed. This applies to all newly created objects, circles, cubes, bolts, everything. Pressing F6 brings up the tweaking panel as well but the same thing is happening, none of the values can be changed. Did I just accidently hit a key stroke to make them unaccessible or is this a glitch? Any suggestions? Thanks.

Save your file, close then restart blender. I’ve seen this happen after an addon raising some python error.

Thanks. I tried that but the problem still exists.

I have even uninstalled Blender and then reinstalled it. The problem is still there. It’s almost like I switched something off but am not able to turn it back on. Heeeeeeeeeelp!

Have you tried File > Load Factory settings?

Cheers, mib.

Good idea, mib. That worked. Now I just have to redo my user preferences, but that is OK. I also found that if I add new objects in the edit mode it also works, but not adding new objects in the object mode. I will go with what you suggest. Thanks very much.