private void applyHeightMap(object sender, EventArgs e)
 {
     Cursor.Current = Cursors.WaitCursor;
     if (!isHeightMapApplied)
     {
         loadHeightMap(sender, e);
         codeBeforeHeightMap.Clear();
         foreach (string codeline in fCTBCode.Lines)
         {
             if (codeline.Length > 0)
             {
                 codeBeforeHeightMap.AppendLine(codeline);
             }
         }
         VisuGCode.getGCodeLines(fCTBCode.Lines);
         fCTBCode.Text = VisuGCode.applyHeightMap(fCTBCode.Lines, _heightmap_form.Map);
         update_GCode_Depending_Controls();
         _heightmap_form.setBtnApply(isHeightMapApplied);
         isHeightMapApplied = true;
     }
     else
     {
         fCTBCode.Text = codeBeforeHeightMap.ToString();
         update_GCode_Depending_Controls();
         _heightmap_form.setBtnApply(isHeightMapApplied);
         isHeightMapApplied = false;
     }
     Cursor.Current = Cursors.Default;
 }