Floating action button's shadow clipping at view margins

Question

I have a floating action button anchored to the bottom right of a coordinator layout. It is 16dp from the margins of the view (the margins are included by default and specified in the dimens.xml file), but its shadow is clipping and has a square-shape appearance (see below). When I move the floating action button to 32dp from the margins of the view, its shadow displays properly.

I have tried setting its elevation attribute (android:elevation="5dp"), but that seems to have no effect. I have also tried setting the attribute borderWidth to 0 (app:borderWidth="0dp") but that also had no effect.

Is there a reason the floating action button is behaving like this?

XML

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/coordinator_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/create_floating_action_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_create_white_48dp"
        app:layout_anchor="@id/coordinator_layout"
        app:layout_anchorGravity="bottom|right" />

</android.support.design.widget.CoordinatorLayout>

Images

Answer 1

The problem is a parent clipping the shadow. Look for the parent that is clipping the shadow (is not necessarily the next in the hierarchy) and add this to the view in the xml.

android:clipChildren="false"

I've been testing this right now removing and adding that line to the parent that was clipping the view and is working fine.

Adding another containers or changing the margins is a workaround that I don't recommend. It's too patchy. The mini fabs have different container sizes and require different sizes depending on the API level (<21 or >=21).