Why does ProGuard not obfuscate these classes?

Question

I am trying to figure out how ProGuard works in an Android project built with Gradle.

Given my Gradle DSL:

    buildTypes {
    debug {
        versionNameSuffix = ".D"
    }
    release {
    }
    all {
        minifyEnabled = true
        proguardFile "proguard-configur.txt"
    }
}

And given my proguard-configur.txt file:

# Allow obfuscation of android.support.v7.internal.view.menu.**
# to avoid problem on Samsung(and other) 4.2.2 devices with appcompat v21
# see https://code.google.com/p/android/issues/detail?id=78377
-optimizations !class/merging/*,!code/allocation/variable
-keepattributes **
-keep class !android.support.v7.internal.view.menu.**,** {*;}
-keep class !android.support.** {*;}
-dontpreverify
-dontwarn **

The behaviour I would expect here is to keep all classes but the support library, therefore, the support library would be obfuscated and optimized. Nevertheless, it is not optimized and doesn't seem to be obfuscated either:

<root>: 64710
    <default>: 1
    android: 15856
        accessibilityservice: 6
        accounts: 23
        animation: 38
        app: 437
        appwidget: 7
        bluetooth: 2
        content: 397
            pm: 85
            res: 95
        database: 91
            sqlite: 23
        graphics: 275
            drawable: 85
                shapes: 2
            pdf: 3
        hardware: 4
            display: 3
        location: 35
        media: 200
            session: 72
        net: 62
            http: 6
            wifi: 6
        os: 236
        preference: 22
        print: 22
            pdf: 5
        provider: 15
        speech: 6
            tts: 6
        support: 12406
            annotation: 3
            v4: 7030
                accessibilityservice: 41
                app: 1438
                content: 232
                    pm: 1
                    res: 8
                database: 3
                graphics: 122
                    drawable: 96
                hardware: 19
                    display: 19
                internal: 74
                    view: 74
                media: 1108
                    routing: 96
                    session: 766
                net: 64
                os: 21
                print: 82
                provider: 96
                speech: 14
                    tts: 14
                text: 88
                util: 265
                view: 2290
                    accessibility: 847
                widget: 1072
            v7: 5373
                app: 458
                appcompat: 15
                cardview: 8
                gridlayout: 7
                internal: 2172
                    app: 267
                    text: 3
                    transition: 2
                    view: 608
                        menu: 512
                    widget: 1290
                recyclerview: 1
                view: 25
                widget: 2687
        telephony: 4
        text: 53
            method: 3
            style: 4
        transition: 16
        util: 66
        view: 807
            accessibility: 164
            animation: 35
            inputmethod: 3
        webkit: 73
        widget: 553

So, the question is clear: Why is not android.support and descendants obfuscated and optimized?

Answer 1

I think it should be minifyEnabled true not minifyEnabled = true at least it is like this in my build.gradle file and obfuscation works.

Answer 2

I don`t know, but you can check why proguard keeping the classes with: http://proguard.sourceforge.net/manual/usage.html

search for -whyareyoukeeping