Why is the right-click menu in the wrong place in the chrome extension options ui?

I'm working on a google chrome extension, using the new options page (declared in the manifest as "options_ui"). In the last week or so, I started seeing this issue:

When I right-click in the options page, the context menu appears far to the right of where I clicked. In addition, the dropdown list of a <select> element also appears far to the right, rather than under the select element where it should go.

I have reproduced this issue on different machines, with different chrome accounts. I tried it out with a bare-bones extension just to make sure. Here is my manifest:

{
"name": "test",
"version": "1.0",
"manifest_version": 2,
"description": "check out options page bug",
"browser_action": {
    "default_popup": "popup.html"
},
"options_ui": {
    "page": "options.html"
}
}

And my options.html:

<!DOCTYPE HTML>
<html lang="en">
<head>
    <title>test</title>
</head>
<body>
    <select>
        <option>one</option>
        <option>two</option>
        <option>three</option>
    </select>
</body>

Does anybody know why this is happening and what I can do to fix it?