explicitMarginBetweenDropdownAndTarget property
Why
While DropdownAlignment is also capable of providing margin between the target and the dropdown, situation sometimes calls for explicit margins in pixels. This is the param for that.
But
If you use this with alignment positions that position the dropdown over the target widget -- the dropdown is positioned in such a way that you don't really see any margin, because it's right on top of the target widget, then using this is pointless.
Implementation
final double explicitMarginBetweenDropdownAndTarget;