The cursor on the emoji categories dialog is changed through moving mouse cursor on it though, moving the cursor with keyboard doesn't follow it.

Reproducible: Always

Steps to Reproduce:
1.Press Super+period and space to show the categories dialog
2.move the cursor through mouse to somewhere else
3.press down-arrow key
Actual Results:  
The cursor moves down where it initially pointed at. i.e. 2nd item at the list in this case.

Expected Results:  
The cursor should moves down where the mouse cursor pointed at the list. e.g. if it points to 4th item after step 2, the cursor should move down to 5th item.