Always paste plain text

app/src/main/java/eu/faircode/email/EditTextCompose.java

@@ -0,0 +1,29 @@
+package eu.faircode.email;
+
+import android.content.Context;
+import android.os.Build;
+import android.util.AttributeSet;
+
+import androidx.appcompat.widget.AppCompatEditText;
+
+public class EditTextCompose extends AppCompatEditText {
+    public EditTextCompose(Context context) {
+        super(context);
+    }
+
+    public EditTextCompose(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public EditTextCompose(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    @Override
+    public boolean onTextContextMenuItem(int id) {
+        if (id == android.R.id.paste && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
+            return super.onTextContextMenuItem(android.R.id.pasteAsPlainText);
+        else
+            return super.onTextContextMenuItem(id);
+    }
+}

app/src/main/res/layout/fragment_compose.xml

@@ -176,7 +176,7 @@
                 app:layout_constraintStart_toStartOf="parent"
                 app:layout_constraintTop_toBottomOf="@+id/tvNoInternetAttachments" />
 
-            <EditText
+            <eu.faircode.email.EditTextCompose
                 android:id="@+id/etBody"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"