Syntax underlining not working in Sublime Text 2

Question

I'm using Sublime Text 2 build 2217 on OSX 10.8.2. Everything else works great, except I can't get underlining to work. Here's an example from my theme file:

    <dict>
        <key>name</key>
        <string>Language Constant</string>
        <key>scope</key>
        <string>constant.language</string>
        <key>settings</key>
        <dict>
            <key>fontStyle</key>
            <string>bold italic underline</string>
            <key>foreground</key>
            <string>#FF1308</string>
        </dict>
    </dict>

In ST2, a Python language constant like True or False shows up in red with bolded italic text, like expected, but not underlined like it would show up in TextMate. It doesn't matter the language or context, I can't get underlining to work. The only thing that does work is bracket matching, which does show a thin underline for matching pairs. Any suggestions?