Add an empty state, when there are no configurations, showing a label indicating that the list is empty

Contributes to CURA-5876.

resources/qml/Menus/ConfigurationMenu/ConfigurationListView.qml

@@ -7,16 +7,15 @@ import QtQuick.Controls 2.3
 import UM 1.2 as UM
 import Cura 1.0 as Cura
 
-Column
+Item
 {
     id: base
     property var outputDevice: null
-    height: childrenRect.height + padding
+    height: childrenRect.height
-    spacing: UM.Theme.getSize("narrow_margin").height
 
     function forceModelUpdate()
     {
-        // FIXME For now the model should be removed and then created again, otherwise changes in the printer don't automatically update the UI
+        // FIXME For now the model has to be removed and then created again, otherwise changes in the printer don't automatically update the UI
         configurationList.model = []
         if (outputDevice)
         {
@@ -24,6 +23,17 @@ Column
         }
     }
 
+    // This component will appear when there is no configurations (e.g. when loosing connection)
+    Label
+    {
+        width: parent.width
+        visible: configurationList.model.length == 0
+        text: "Configuration list empty. Probably because of lost connection"  // TODO change this to a proper component
+        horizontalAlignment: Text.AlignHCenter
+        wrapMode: Text.WordWrap
+        renderType: Text.NativeRendering
+    }
+
     ScrollView
     {
         id: container

resources/qml/Menus/ConfigurationMenu/ConfigurationMenu.qml

@@ -35,7 +35,6 @@ Cura.ExpandablePopup
     }
 
     contentPadding: UM.Theme.getSize("default_lining").width
-    contentAlignment: Cura.ExpandablePopup.ContentAlignment.AlignLeft
     enabled: Cura.MachineManager.hasMaterials || Cura.MachineManager.hasVariants || Cura.MachineManager.hasVariantBuildplates; //Only let it drop down if there is any configuration that you could change.
 
     headerItem: Item
@@ -130,18 +129,19 @@ Cura.ExpandablePopup
     {
         id: popupItem
         width: UM.Theme.getSize("configuration_selector").width
-        height: implicitHeight //Required because ExpandableComponent will try to use this to determine the size of the background of the pop-up.
+        height: implicitHeight  // Required because ExpandableComponent will try to use this to determine the size of the background of the pop-up.
         padding: UM.Theme.getSize("default_margin").height
         spacing: UM.Theme.getSize("default_margin").height
 
-        property bool is_connected: false //If current machine is connected to a printer. Only evaluated upon making popup visible.
+        property bool is_connected: false  // If current machine is connected to a printer. Only evaluated upon making popup visible.
+        property int configuration_method: ConfigurationMenu.ConfigurationMethod.Custom  // Type of configuration being used. Only evaluated upon making popup visible.
+
         onVisibleChanged:
         {
-            is_connected = Cura.MachineManager.activeMachineNetworkKey !== "" && Cura.MachineManager.printerConnected //Re-evaluate.
+            is_connected = Cura.MachineManager.activeMachineNetworkKey !== "" && Cura.MachineManager.printerConnected  // Re-evaluate.
+            configuration_method = is_connected ? ConfigurationMenu.ConfigurationMethod.Auto : ConfigurationMenu.ConfigurationMethod.Custom  // Auto if connected to a printer at start-up, or Custom if not.
         }
 
-        property int configuration_method: is_connected ? ConfigurationMenu.ConfigurationMethod.Auto : ConfigurationMenu.ConfigurationMethod.Custom //Auto if connected to a printer at start-up, or Custom if not.
-
         Item
         {
             width: parent.width - 2 * parent.padding

resources/themes/cura-light/theme.json

@@ -356,7 +356,7 @@
 
         "expandable_component_content_header": [0.0, 3.0],
 
-        "configuration_selector": [38.0, 4.0],
+        "configuration_selector": [35.0, 4.0],
         "configuration_selector_mode_tabs": [0.0, 3.0],
 
         "action_panel_widget": [25.0, 0.0],