Sorry for the delay. I can confirm this issue. For pair adjustments you need to hold down the CTRL key, and for some reason this isn’t working with single adjustments. We will fix this with the next upcoming update.
The next upcoming update will position the glyph in the correct vertical placement.
Of all four fields, you can click inside the visible area and adjust these values, except for YAdvance. This value is hardly used, as I think is only useful for vertical writing.