[Lazarus] Docking right border of TDirectoryEdit/TFileNameEdit

[Jürgen Hestermann]

How can I attach the right border of a TDirectoryEdit/TFileNameEdit 
element to the right of the form I put it on?
It seems that the right border of this elements end at the right border 
of the input line so that the icon for mouse selection is on the right 
of the right border.
I would expect the right border of the icon to be the right border of 
the whole element.
If I attach the right border of TDirectoryEdit/TFileNameEdit elements to 
the right of the whole window the icon is no longer visible.
And if I add a right margin it is put *between* the input line and the 
icon so that the icon is no longer directly attached to the input line.
Is that as designed?
I don't see any logic in this?