[UX] Way of hiding elements in descreased width window

Hi there,
I found one thing that really annoys me in MuseScore and I think it could be improved.

I very often transcribe old scores so I split my screen between a PDF and MuseScore.

Because of limited width, some options in the top menu (the one with notes) are hidden (namely - voice selection buttons). There are two problems with that:

1. I think the buttons should be hidden according to their importance, i.e. three and four dots should be hidden before second voice button. Here's a comparison of how the hidding works now (top row) and how it could work (bottom row).
   

2. The other problem is that once one click the [»] to show hidden options, they are aligned to the left. In case of changing voices this is the other side of the window. What worse -- one have to keep hovering over the rolled-out menu or it closes.

I have to patiently and carefully drive my cursor through the whole window to change a voice. Sometimes it takes me 2 or 3 trials before I manage not to move my mouse away from the thin bar.

The simplest fix for that would be aligning the items to the nearest place to the [»] (or simply to the right).

Addressing factors:
- Consistency - preserved
- Ease of adoption - Current approach assumes that users understand the meaning of [»] button. Nothing new is introduced in this regards.
- Quickly perform common tasks - this requires some research on frequency of use of each button; some telemetry would be great (or simply a survey). If done properly it will increase the quickness.
- Flexibility - As above - it would increase time of performing some less important tasks.
- Localisation - not applicable
- Portability - may be considered as an improvement for lower screen resolutions
- Scalability - nothing changes
- Accessibility - hard for me to predict. May have some negative influence in this regard.