When trying to select a color for a new JQL or trying to change the color for existing ones, it's not possible to select a different color.
If someone selected, for example, Green for the High priority, now it's not possible to change the color to Red.
- Go to a Classic software project board > Board settings
- On Card colors, try to change the color for current options or to create a new one based on JQL.
It's possible to select any color.
If the color picker is set to Blue, for example, you will be able to only select Blue colors.
Edit the color code on the right. It has 3 rows, each represents a color, Red, Green, Blue respectively. To change the color to red, enter the value of 255 on the first row and make the 2nd and 3rd row 0. You can refer to the chart below: