ADD question button vs. Assign question button

**Is your feature request related to a problem? Please describe.**
The Add question button and assign question button are too close and look alike each other.
However, they function completely different.
Accidently assign questions instead of add question can be a headache.

**Describe the solution you'd like**
Make the button different color and slight apart from each other.

**Describe alternatives you've considered**
N/A

**Additional context**
N/A