help with removeElement, ties, and other questions

Hi, I have a couple of random questions regarding some plugin functions. Here goes:

1. I want to delete everything in a selection without using cmd("delete") because that will create a separate undo history. so im trying to delete the selection using the plugin, specifically:

   var e = curScore.selection.elements
   for (var i in e) {
        removeElement(e[i]);
   }
   

   Using that, I´m able to remove all the elements, except tulpets!! even if i use:

   if (e[i].type==Element.tuplet) {
   removeElement(e[i].tuplet);
   }
   

   Why is that? what am i missing here?

   But, If there are any chords present in the selection, removeElement seems to stop after deleting the bottom note of the first chord and does not delete anything after that. Very strange... So it seems to me that there is a special way to delete chords?

however, I am able to delete chords and tuplets using a the segment approach:

 while(cursor.segment && cursor.tick < endTick ) {                   
    var e = cursor.element;         
    if(e.tuplet) {
        removeElement(e.tuplet); // must specifically remove tuplets
    }                           
    else {
        removeElement(e); 
    }           
    cursor.next();                  
 }

though, this method does not delete trills, hairpins, chord symbols...

I feel there is a better way to solve this using the first approach, though i have no idea how.

Could anyone please explain to me what is happening here?

2. Is there a way for a plugin to continue a count from an previous run. In other words, i need to access a variable´s value from the last time i run the plugin. Any clue how to do thtat?

3. Is is possible to change an existing note´s duration from it´s properties without having to delete it and add it again with a different duration? ( i need to preserve tiebacks /slurs and any articulation dynamics etc.. attached to that note)

4. I´ve studied the code for the retrograde plugin and have been using a similar way to copy and paste notes. How can i detect if a tie exists on a note/chord? and how can i add ties to notes?

I appreciate all the help I can get.