qml: Show 4 proper indicators when dragging in a floating window

They don't do much yet, but at least appear.

src/private/quick/qml/ClassicIndicatorsOverlay.qml

@@ -1,7 +1,44 @@
 import QtQuick 2.9
+import com.kdab.dockwidgets 1.0
 
-Rectangle {
+Item {
     id: root
-    color: "blue"
     anchors.fill: parent
+    readonly property int outterMargin: 10
+
+    ClassicIndicator {
+        indicatorType: DropIndicatorOverlayInterface.DropLocation_OutterLeft
+        anchors {
+            left: parent.left
+            leftMargin: outterMargin
+            verticalCenter: parent.verticalCenter
+        }
+    }
+
+    ClassicIndicator {
+        indicatorType: DropIndicatorOverlayInterface.DropLocation_OutterRight
+        anchors {
+            right: parent.right
+            rightMargin: outterMargin
+            verticalCenter: parent.verticalCenter
+        }
+    }
+
+    ClassicIndicator {
+        indicatorType: DropIndicatorOverlayInterface.DropLocation_OutterTop
+        anchors {
+            top: parent.top
+            topMargin: outterMargin
+            horizontalCenter: parent.horizontalCenter
+        }
+    }
+
+    ClassicIndicator {
+        indicatorType: DropIndicatorOverlayInterface.DropLocation_OutterBottom
+        anchors {
+            bottom: parent.bottom
+            bottomMargin: outterMargin
+            horizontalCenter: parent.horizontalCenter
+        }
+    }
 }