Check or uncheck this check box to show or hide the marks.
Use Contour Line Colors
Check this check box to use the same colors for the mark texts as those used
the corresponding contour lines. In such a case, the color specified on the Text
tab-page is ignored.
Check this check box to avoid the overlapping of the marks.
The value in this spin box controls the density of the marks.
The value in this spin box specifies the margin of the marks.