Scrollbar position changing when using Mute Myself

**Describe the bug**
When I select the "Mute Myself" option, the position of the scrollbars are reset to the default in the mixingboard
This occurs for both the horizontal and vertical scrollbar.
Most likely caused by the "red" label which is shown or will be hidden when the "Mute Myself" status is changing

**To Reproduce**
Ensure the mixingboard is showing horizontal and/or vertical scrollbars.
Move the scrollbars to a position other then the default.
Select the "Mute Myself" option, the position of the scrollbars is reset to the default (horizontal moves to left, vertical moves to bottom).
Changing the position again to a custom position.
Select the "Mute Myself" option, the position of the scrollbars is reset to the default.

**Expected behavior**
Scrollbar should retain the selected position.

**Screenshots**

**Operating system**
Win 10

**Version of Jamulus**
v3.7.0

**Additional context**
I have noticed a potential new GUI, in which the "red" bar is placed different and does not effect the mixerboard anymore.
Not sure when that will be implemented, hence thought about to still report it here.
Obvious this is mainly an issue with a large group or a small screen. The upcoming changes to allow up to 8 mixer rows might also resolve this, but guessing there still will be people with smaller screen which cannot fit 3 or more rows.

Reproduce the issue in the Jamulus v3.7.0 mixingboard on Windows 10 with both scrollbars moved from their defaults. Trace the GUI handling of the "Mute Myself" state and the mixingboard scrollbar position, then verify that toggling mute preserves both horizontal and vertical positions.

Written by the indexing model from the issue text.