Description
When you select a part in workspace and click the “BrickColor” option in properties section…the panel that then appears when you further select “More Colour” it brings up a Color3 selection panel. When you select a colour on here there is no “Ok” or confirmation button so the part selected never changes to the chosen colour.
Example
Here’s a GIF of what I mean:
As a reference point here’s what happens when you click directly on the Colour3 option in the properties bar (The “Ok” button appears on the selection panel):