Fix using ConnectorResource icons before attaching ComboBox (#10810)

* Fix using ConnectorResource icons before attaching ComboBox

* Update Chrome and PhantomJS screenshots

1 files changed, 11 insertions, 0 deletions

diff --git a/server/src/main/java/com/vaadin/ui/ComboBox.java b/server/src/main/java/com/vaadin/ui/ComboBox.java
index ef1e7cfa84..107e503256 100644
--- a/server/src/main/java/com/vaadin/ui/ComboBox.java
+++ b/server/src/main/java/com/vaadin/ui/ComboBox.java
@@ -842,6 +842,10 @@ public class ComboBox<T> extends AbstractSingleSelect<T>
             Resource icon = getItemIconGenerator().apply(value);
             if (icon != null) {
                 if (icon instanceof ConnectorResource) {
+                    if (!isAttached()) {
+                        // Deferred resource generation.
+                        return;
+                    }
                     setResource("selected", icon);
                 }
                 selectedItemIcon = ResourceReference
@@ -852,6 +856,13 @@ public class ComboBox<T> extends AbstractSingleSelect<T>
     }
 
     @Override
+    public void attach() {
+        super.attach();
+
+        updateSelectedItemIcon();
+    }
+
+    @Override
     protected Element writeItem(Element design, T item, DesignContext context) {
         Element element = design.appendElement("option");