Scatterplot with 4 custom colours on select?

Hi acg 
Thank you  for reaching out to the Microsoft fabric community forum.

You can solve this by creating a separate table for selecting the entity, so it doesn’t filter the main data. Then use a DAX formula to set colours based on which entity is selected and whether it's flagged or not. This way, all entities will always show in the scatterplot selected one in dark colour, others in light colour. Just use EntityColor in legend, and FlagStatus on X-axis and Score on Y-axis. It will work exactly like you want.
Instead of using a table, I suggest using a slicer to select the entity. It will help show all entities in the scatterplot with correct highlight and color logic as you expected.

I tested it with my sample data, and it worked fine. Please find the attached Pbix for your reference and gothrough with this link it may help you regarding issue:
Solved: Change color of scatter depending on selection fro... - Microsoft Fabric Community
I hope this helped Feel free to ask any further questions. If this resolved your issue, please mark it as "Accept as Solution" and give us Kudos to assist others.

Regards,
Harshitha.