I found memory is growing and GC is running when FreeFlow is shown even if I didn't touch to the device.
Allocation tracking says FreeFlow is computing layout constantly.

image

It was because FreeFlowContainer is placed in RelativeLayout and layout_above is used.
(I placed LinearLayout with fixed height of 76dp, which contains Buttons, on the bottom of fragment.)
For workaround I applied below diff to my xml file.

 <FreeFlowContainer
 android:layout_width="match_parent"
- android:layout_height="wrap_content"
+ android:layout_height="match_parent"
 android:layout_alignParentTop="true"
- android:layout_above="@id/footerButton"
+ android:layout_alignParentBottom="true"
+ android:layout_marginBottom="76dp"

This issue also causes bug that sometimes onItemSelected() is not called.