Fullscreen inbox overlay broken

### Description
GooseMod Fullscreen Inbox plugin overlay seems to be broken as seen here.
![image](https://user-images.githubusercontent.com/45357714/131217698-be0293c4-e29b-4631-84c3-0d2bab197c35.png)

### System Information
```
Static hostname: pop-os
Operating System: Pop!_OS 21.04
Kernel: Linux 5.11.0-7620-generic
Architecture: x86-64
```