Why is my script undoing half its work before it's done?

So blends have some annoying, unconfigurable behavior: if you have open paths in your blend then Illustrator won't automatically create a blend spine, and it insists on checking "knockout group" on the blend, which I almost never want.

I have a script that attempts to work around this. It saves the open/closed state of every selected path, makes them all closed, calls object>blend>make, unchecks knockout group, and attempts to restore the original open/closed state (but this doesn't seem to take any more).

Then it calls object>blend options. Because I almost inevitably do that after creating a blend. And this is where things get weird: the instant I start poking at the options in that window, everything my script did is *undone*. What the heck is going on here?

(And why does my loop that is supposed to restore the open/closed state of each path not seem to do anything half the time, either?)

// blend properly

#target Illustrator
#targetengine main

function Main(curDoc, sel, amountofselectedobjects) {
	// we just fail silently if <2 paths are selected,
	// just like the normal blend operation
	if (amountofselectedobjects >= 2) {
		firstPath = sel[0];
	
	pathClosed = new Array();
	
	// record closed/open state of all paths, close them all
	for (var i = 0; i < amountofselectedobjects; i++) {
		pathClosed [i] = sel[i].closed;
		sel[i].closed = true;
		// alert (pathClosed[i]);
	}
	
	app.executeMenuCommand('Path Blend Make');

	// Illustrator thinks blends should default to having 'knockout group' turned on and I never want this.
	firstPath.parent.parent.artworkKnockout = KnockoutState.DISABLED;
	
	// attempt to restore closed/open status
	// why does everything stay closed
	// even though my diagnostic alert returns a few 'false'es
	for (var i = 0; i < amountofselectedobjects; i++) {
		sel[i].closed = pathClosed [i] ;
		alert (pathClosed[i]);
	}
	
	// I would like to immediately pop up the blend options but for some reason
	// this undoes the blend creation when I start cursoring around
	// in the blend options window, wtf.	
	app.executeMenuCommand('Path Blend Options');
	
	}
}


// initial setup: check for open document, fail quietly or invoke main function
if ( app.documents.length > 0 ) {
	var curDoc = app.activeDocument;
	
	var sel = curDoc.selection; // get selection Pageitems
	var amountofselectedobjects = sel.length;
	
	Main(curDoc, sel, amountofselectedobjects);
}


 

 (also happy slightly belated seventh birthday to my uservoice request regarding this behavior)

Thanks for any wisdom y'all have to bring to this problem. 🙂