You will need to give more information about what you are doing. It might even be a hardware problem...however
I can make a new palette in several ways. This from an existing image.
![01-pallete.jpg](./download/file.php?id=42365&sid=41953f43d2b840a1f180ff8f697545a8)
- 01-pallete.jpg (135.33 KiB) Viewed 4353 times
That gets a new palette, saved in the Gimp profile: C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\palettes. Click on that opens the palette editor dock.
That is editable but can be used to set the Foreground (FG) colour for painting with a
single click. Can be edited but that required a double click. Maybe that is the problem.
![02-palette.jpg](./download/file.php?id=42366&sid=41953f43d2b840a1f180ff8f697545a8)
- 02-palette.jpg (149.99 KiB) Viewed 4353 times
Other possibilities: Using the Color History. This gets the colours from the FG/BG color picker, so it will change. If you need to reset it delete the
colorrc file in the Gimp profile.
![03-palette.jpg](./download/file.php?id=42367&sid=41953f43d2b840a1f180ff8f697545a8)
- 03-palette.jpg (141.87 KiB) Viewed 4353 times
Non-editable palette: The stock palettes that come with Gimp are in C:\Program Files\GIMP 2\share\gimp\2.0\palettes. This is read only. Move your custom palettes there.
Check the location in Edit -> Preferences -> Folders -> Palettes.
![Image](https://i.imgur.com/UHMKjam.jpg)
or it might be something else