It is better to reset the line width after having finished to draw with a modified width.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12146 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

test/offscreen.cxx

@@ -220,6 +220,7 @@ void oscr_box::oscr_drawing(void)
     ox = ex;
     oy = ey;
   }
+  fl_line_style(FL_SOLID, 0);
   fl_end_offscreen(); // close the offscreen context
   redraw();
 } // oscr_drawing