Weird behaviour working on a channel

[derekfountain]

Working on an RGB image, I hit Ctrl-3 to get to the blue channel, then opened CM3. It comes up with the channel data image and the blue curve graphic, all as expected. The mode selector radios are greyed out, also as expected.

The mode selector on the ribbon and the image context menu are still active though. Strange things happen when they are clicked; I won't bother explaining them. CM3 is clearly getting into a situation which it shouldn't be able to get into and which it clearly doesn't know how to deal with.

[-default]

Thanks - another reproducible bug that will be easy to fix.