Fix use of HEIGHT_DIALOGBORDER:

Fix use of HEIGHT_DIALOGBORDER:
- its value was ignored (always used the default value 1)
- the menu didn't handle correctly it anyway

Note:
MARGIN_BOTTOM, MARGIN_LEFT and MARGIN_RIGHT must be changed according to HEIGHT_DIALOGBORDER, as the code DON'T handle directly the border size, while MARGIN_TOP is intended as the distance from the title bar and doesn't depend on HEIGHT_DIALOGBORDER.
FONTSIZE_TITLE and HEIGHT_TITLE must NOT be changed according to HEIGHT_DIALOGBORDER because they change the borders too (I don't know why they behave in this way).