Layer Style dialog box: move effect up/down arrow buttons disabled

[Boodlums _]

Why are the move effect up/down arrow buttons disabled?

They even appear disabled in Adobe's own screenshots. Is it just to taunt us?

[Jeff Arola]

You need to add more than one layer effect of the same kind.

For example, if you add three Drop Shadows using the +, then clicking on the middle

Drop Shadow, both up and down arrows are enabled.

https://helpx.adobe.com/photoshop/using/layer-effects-styles.html