jquery mobile trigger create enchances some elements but not all - ajax

Question

I think this may be a bug in Jquery Mobile, but it could also be user error (mine).
For a jquery mobile page, I am manually calling $(..).trigger("create") after loading in some html asynchronously. I am finding an odd - to me anyway - behaviour, which is that <input>s of type text on the loaded html are not enhanced to have JQM's styling, whereas <input>s that are of type button are.
Here's a stripped-down version that replicates the problem. Basically, a page loads and injects foo.html. Part of foo.html is a placeholder div that is subsequently loaded and injected with bar.html. bar.html contains a link that opens a popup. When it's clicked and the popup opens, buttons are styled correctly; inputs are not.
Note: I call trigger("create") on the parent of the injected content.
Further note: calling trigger("create") on the grandparent of where bar.html is injected makes everything be styled correctly, including inputs on the popup. See below for code.
in the body of my basic html page:
<div data-role="page" id="grandparent" data-theme="a">
<h3>A very basic page</h3>
</div>
the script in that page's head:
<script type="text/javascript">
$(document).ready(function() {
var path = "pathToFiles/";
$("#grandparent").load(path + "foo.html", null, function() {
$("#grandparent").trigger("create");
//now load bar
$("#bar_placeholder").load(path + "bar.html", null, function() {
/*this does NOT enhance text <input> on popup*/
$("#bar_placeholder").trigger("create");
/*this DOES enhance text <input> on popup*/
//$("#grandparent").trigger("create");
});
});
});
</script>
here is foo.html
<div data-role="content" id="foo">
<h3>Foo before placeholder...</h3>
<div id="bar_placeholder" data-role="content"></div>
<h3>...foo after placeholder</h3>
<label for="foo_input" class="ui-hidden-accessible">foo input IS enhanced:</label>
<input id="foo_input" value="" placeholder="i AM enhanced" data-theme="a" type="text" />
<input type="button" id="foo_button" value="Foo Button"/>
</div>
and here is bar.html:
bar popup button
<div data-role="popup" id="popupLogin" data-theme="a" class="ui-corner-all">
<h3>Bar header</h3>
<label for="bar_input" class="ui-hidden-accessible">bar text input NOT enhanced</label>
<input name="bar_input" id="bar_input" placeholder="i am NOT enhanced" data-theme="a" type="text"/>
<input type="button" data-theme="a" value="bar button"/>
</div>