The field starts out left-aligned, which is not too bad. The image above shows the field after modification, which is right aligned and make it rather difficult to manage.
Maybe if @brad could extend the field to the left? … which would break the alignment of the input boxes, but might work in this case …
are you aware that the Binding editor can be re-sized? Once you make the dialog a bit wider, the note field will grow with it, while Channel stays constant in width. Now the whole note will fit in the field.