Deree stem mixer does not look right.

### Bug Description

<img width="353" height="153" alt="Image" src="https://github.com/user-attachments/assets/4369292e-6e40-4e50-8d7d-70347e56a8d6" />

The handle of the quick effect combobox overlaps with the quick effect knob. 
The --- is missing fir the lower quick effects.
Do we want the stem label all capitals?  



### Version

2.6-beta

### OS

Ubuntu 22.04 