CSS Spy: fix NPE in WidgetTreeProvider #1381

for items that can not be styled with CSS

#1381

Author: jukzi

features/org.eclipse.pde.spies-feature/feature.xml

@@ -2,7 +2,7 @@
 <feature
       id="org.eclipse.pde.spies"
       label="%featureName"
-      version="1.0.400.qualifier"
+      version="1.0.500.qualifier"
       provider-name="%providerName"
       license-feature="org.eclipse.license"
       license-feature-version="0.0.0">

ui/org.eclipse.pde.spy.css/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %name
 Bundle-SymbolicName: org.eclipse.pde.spy.css;singleton:=true
-Bundle-Version: 0.13.400.qualifier
+Bundle-Version: 0.13.500.qualifier
 Automatic-Module-Name: org.eclipse.pde.spy.css
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Require-Bundle: org.eclipse.core.runtime;bundle-version="3.29.0",

ui/org.eclipse.pde.spy.css/src/org/eclipse/pde/spy/css/WidgetTreeProvider.java

@@ -58,7 +58,9 @@ public Object[] getChildren(Object parentElement) {
 		NodeList kids = element.getChildNodes();
 		ArrayList<Object> children = new ArrayList<>(kids.getLength());
 		for (int i = 0; i < kids.getLength(); i++) {
-			children.add(((CSSStylableElement) kids.item(i)).getNativeWidget());
+			if (kids.item(i) instanceof CSSStylableElement kid) {
+				children.add(kid.getNativeWidget());
+			}
 		}
 		return children.toArray();
 	}