"source contains no colors" despite following the instructions to import palette

[gnuimpcub]

My system: Gimp 2.8.18 on Debian GNU/Linux 9 (stretch) 64-bit Gnome 3.22.2

Hi,

I try to import a color palette from a picture with RGB mode, following the instructions of rich2005 found in https://www.gimp-forum.net/Thread-How-to...83#pid6383

Quote:To get a palette from the original RGB image is different.
1. In the palettes dialogue, right click to import https://i.imgur.com/iF437h3.jpg
2. You get the 'Import' dialogue where you can select the image, and the number of colours https://i.imgur.com/qLPGDYU.jpg
3. Then again, hunt for that palette (Lenna-imported-5), right click, rename to something sensible, note the 500 colours in this one. https://i.imgur.com/QBZPIJX.jpg

Try as I might, I always get the message "source contains no colors", and the resulting imported color palette contains only very few colors, e.g., only two.

However, when I first convert the mode of the image to indexed I can import the full color palette containing all colors.

Did I get something wrong with "To get a palette from the original RGB image..."?

Is it impossible to import a color palette from an RGB image?

Thanks,

gnuimpcub

P.S. Since I work with layers, I have to work with RGB mode.

---

Just tried it with Gimp 2.8.16 on Microsoft Windows 10 Home Edition OEM, Version 1511 (Build 10586.164). Same result as with Linux Debian