[Inkscape-user] Colours shown differently after using palette?

Hi everyone, writing to the list since now that the Launchpad presence is discontinued, I couldn't find a "questions" section on Gitlab... I'm new to using swatches/palettes, so I assume I'm doing something wrong. I have a file, looking at the top layer (normal blend mode, all others invisible). Since I started using a certain swatch, all the colours, including those in the palette, are more dull - in the attached image compare the Fill field to the rectangle... This persists through closing and re-opening. What did I mess up? Best, Chris