down menu for all opened tabs

### Description of the new feature

basically what browsers like firefox and chrome doing when tabs mount up scrolling becoming unwieldy.

### Proposed technical implementation details

given there's already a drop down menu on the right hand side, this menu ideally be placed on the left hand side.

Start by locating the existing right-hand dropdown and the tab UI that tracks open tabs. Review how the current menu is populated and how tab selection works. Done means a corresponding left-side menu can expose all open tabs when many tabs make scrolling unwieldy.

Written by the indexing model from the issue text.