void PreviousLine()
 {
     ClearKilledTextBuffer();
     if (marked)
     {
         SciControl.LineUpExtend();
     }
     else if (CompletionList.Active)
     {
         CompletionList.HandleKeys(SciControl, Keys.Up);
     }
     else
     {
         SciControl.LineUp();
     }
 }
 void NextLine(object sender)
 {
     ClearKilledTextBuffer();
     if (marked)
     {
         SciControl.LineDownExtend();
     }
     else if (CompletionList.Active)
     {
         CompletionList.HandleKeys(SciControl, Keys.Down);
     }
     else
     {
         SciControl.LineDown();
     }
 }