Grab focus when the dialog is hidden

This ensures that all components in the loader lose the focus and thus trigger an update

CURA-9523

resources/qml/Preferences/MachinesPage.qml

@@ -93,6 +93,13 @@ UM.ManagementPage
             maximumWidth: minimumWidth * 3
             maximumHeight: minimumHeight * 3
             backgroundColor: UM.Theme.getColor("main_background")
+            onVisibleChanged:
+            {
+                if(!visible)
+                {
+                    actionDialog.loader.item.focus = true
+                }
+            }
         }
 
         UM.ConfirmRemoveDialog