Well, just a personal thought:
I'd enlarge the scroll bar on the right side menu.
Actually it's barely visible and almost impossible to grab using mouse...
or allow the scroll using the mouse wheel when the mouse is over the menu ?
it would leave space, and still allow to scroll the menu.
With mouse it is not nessessary to use this scroll bar at all. It is only information for your eyes. Just position mouse to what ever place on side menu, and drag with the mouse left button pressed.
Just same as you do without mouse with finger (somehow same kind of logic, finger press (touch) screen and drag. With mouse, finger touched (pressed) left button and drag moving mouse.
Still I hope Siglent think again what is right place for "return" button in menu. My opinion is that it need be visible always so that if I open what ever menu and if want return to previous menu no need scroll for find return button.
Sidenote / cannot be done with the mouse wheel. There need do redesign so many things if do this. Now with mouse + left button it works well.
The mouse wheel has another important function in menus and should not be interfered with in any way. Namely, if we use the scroll to move the menu, what about when the cursor hits the field during the move where we use the scroll to change the numeric value. The result was a complete mess.