Being not so familiar with the mathematical and statistical methods of processing images, I pay special attention at user interfaces and comfort of using any software.
In the panorama editor adding and moving control points is done with the
left mouse button. It is hard to work with control points using only
the left button, often a new point is added instead moving an
existing one.
Moving the zoomed image left using the wheel left is not working in some controllers.
Some quick actions are available from keyboard shortcuts. Manual work with editing control points, adding straight lines often requires to look at the images from some distance, the keyboard is sometimes out of reach. Sometimes the other hand is operating a mobile device etc.
My suggestion is to improve the Panorama Editor engaging all mouse buttons.
Left click = move a control point
Right click = add a new point (or alternatively, depending on user's choice)
Mouse wheel up = zoom +
Mouse wheel down = zoom - (the default zoom factors - fit to window, 25% - 200%)
Wheel click = fine tune the active pair of control points
Left click and move mouse = move the zoomed image.
Buttons previous / next, available in many controllers = jump to the prev / next image pair