Android ImageButton does not display image, even though it is visible in the Designer preview

i am trying to create an Image Button in Android Studio. The Designer preview shows the image correctly, but when I run the App there is no image in the Button. Just an empty button as small as possible.

Things I have tried:

• Copying the image from the Android drawable folder into my own drawable folder
• Creating a placeholder image because of a bug the prevents the first image in the folder to not show up, according to some sources on stackoverflow
• Using different images

None of this worked for me. It is like the whole function is just broken. The interesting part is, when I set the image I want as the background of the imagebutton it works fine. But it looses its "button-appearence", so thats not a solution for me.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

<org.osmdroid.views.MapView android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent" />

<LinearLayout
    android:id="@+id/search_ui"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:padding="1dp"
    android:background="@color/white"
    android:orientation="horizontal">
    <ImageButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/ic_menu_manage"
        android:id="@+id/imageButton"/>
    <EditText android:id="@+id/edit_search_string"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="@string/search_string" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_send"
        android:onClick="myClickHandler"/>
</LinearLayout>

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="5dp"
    android:background="@color/white"
    android:layout_below="@id/search_ui">
    <TextView
        android:id="@+id/display"
        android:textSize="16sp"
        android:textStyle="bold"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="New Text" />
</LinearLayout>

try using only src instead of srcCompat and see if it works