uneditable layers in Gimp xfc file

[kalpana]

I know I may need to ask this at the Gimp forum, but that means I'd need to register (lazy, I know!). Hopefully someone here can help.

I have a Gimp (2. file in layers that I saved in the native xcf format so that I could later edit the layers. However, when I re-opened the file I discovered I could not edit some of those layers.

Previously I saved-as the file under another name so I could export it as a flattened bitmap. It is those layers that I cannot edit in the original xcf file. What did I do wrong?