BitmapDrawable turns out is sort of immutable even when using mutate()
so what was happening was that when switching from a tab on the right to
a tab on the left, the foreground drawable was set as the background of
two views for a small instant as the RecyclerView binds views from left
to right and the setColorFilter on the left foreground tab was not
working at all. When you switched from a left to right tab, it worked
fine because the left tab background was changed before the right and
the foreground drawable was only used by one view in that case. The
solution was to not reuse the drawable but instead reuse the backing
bitmap and create a new drawable whenever a tab moved to the foreground.
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