Strange behavior with spell object

Question

Here is a small example (pretty much the same as the example on http://livedocs.adobe.com/acrobat_sdk/9.1/Acrobat9_1_HTMLHelp/wwhelp/wwhimpl/js/html/wwhel p.htm?href=JavaScript_SectionPage.70.1.html&accessible=true for
checkWord). The following bare minimum program adds a menu item to Acrobat under the Help menu.
**QUESTION**
If I comment out one line in the code (Noted as "THIS LINE" below), Acrobat *does not* create Squiggly lines under the spell misses. If I leave the line in, the script runs as expected. Is this behavior as expected? As far as I can tell it looks like a bug, but I was wondering if there is something I am missing about the spell object, is it always required to call `spell.available` before using the spell object? (I am using Acrobat Pro 9).
app.addMenuItem( {
cName: "CHECK",
cUser: "CHECK",
cParent: "Help",
cExec: "checkfunc();",
nPos: 0
checkfunc = function(){
          var numWords;
          for (var i = 0; i < this.numPages; i++)
            var ckWord = " ";
                    numWords = this.getPageNumWords(i);
                    for (var j = 0; j < numWords; j++)
            　　　           spell.available; // <---- THIS LINE
                              ckWord = spell.checkWord(this.getPageNthWord(i,j));
                              if (ckWord != null)
                                        this.addAnnot
                                         page: i,
                                         type: "Squiggly",
                                         quads:  this.getPageNthWordQuads(i,j),
                                         author: "Me"

Answer 1

It's an odd one... I ran it once (Acrobat Pro XI 11.0.1) and at the first
run it did exit without error on the first page, but then I ran it again,
and it worked fine... I think you're right that there is some sort of
undocumented "feature" where if the spell object is not initialized it
throws an error. The easiest solution is to add a check at the top of your
code. Something like:
if (!spell.available) {
app.alert("Error! The Spelling plug-in is not available.");
return;