Colors changing ... by themselves?

[Gimpy.]

Thank you, Ofnuts and PixLab. The eye dropper seems to be working fine and the image is in RGB mode. I imported a palette for the image to make coloring consistent. But, still pencil, bucket, etc seem to modify the colors when painting. Can't tell what may have been changed. It all seems to have started after playing 'round wirh curves, etc and trying to reduce number of colors with 'posterize'. Ironically now I'm ending up with more tones and shades of colors than planned for!