Android Studio:FloatingActionButton wont disappear (edited)

Question

I'm new to android so excuse me if I it is too obvious.

My first problem is with the FloatingActionButton. I basically only need on FloatingActionButton wich is to save the search, but there is another one that appears only when I run the app and not in the design view(nor text view).. where did that come from and how can I remove it ??

The XML file

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

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


<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="top|end"
    android:layout_marginTop="@dimen/fab_margin_top"
    android:src="@drawable/ic_favorite_24dp"
    android:contentDescription="@string/save_description"

    android:layout_alignParentRight="true"

    android:layout_alignParentStart="false"
    android:layout_alignTop="@+id/tagTextInputLayout" />



<android.support.design.widget.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/URLTextInputLayout"
    android:layout_below="@id/view"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:imeOptions="actionNext"
        android:hint="@string/url_prompt"
        android:singleLine="true"
        android:layout_below="@+id/view"
        android:layout_toRightOf="@+id/URLTextInputLayout"
        android:layout_toEndOf="@+id/URLTextInputLayout" />

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


<android.support.design.widget.TextInputLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/tagTextInputLayout"
    android:layout_below="@id/URLTextInputLayout">
<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="@string/tag_prompt"
    android:imeOptions="actionDone" />
</android.support.design.widget.TextInputLayout>

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/tagTextInputLayout">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="@string/tagged_links"
        android:id="@+id/textView"
        android:gravity="center_horizontal"
        android:textStyle="bold"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:paddingBottom="@dimen/activity_vertical_margin" />

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:id="@+id/recyclerView"
        android:layout_weight="1"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin" />
</LinearLayout>