Missing "Add" button and way to adjust effects?

I have been editing this comp for a couple of days and when I went to edit opacity the scale from 0-100 was gone and so was the “Add: ▶” to add an effect. I am super confused and don’t recall doing anything to remove this, see pics (this was an existing comp that I no longer know how to adjust in terms of the amount. However, after hours I realized that I could use the Properties tab on the left side panel, but it is just inconvenient and hope to have it back. Anyone know how? I have to have this project done soon so any tips are appreciated!