[316209] [content assist] Filtering down JavaScript content assist proposals does not work for qualified types in web pages

bundles/org.eclipse.wst.jsdt.web.ui/src/org/eclipse/wst/jsdt/web/ui/internal/contentassist/JSDTCompletionProposal.java

diff --git a/bundles/org.eclipse.wst.jsdt.web.ui/src/org/eclipse/wst/jsdt/web/ui/internal/contentassist/JSDTCompletionProposal.java b/bundles/org.eclipse.wst.jsdt.web.ui/src/org/eclipse/wst/jsdt/web/ui/internal/contentassist/JSDTCompletionProposal.java
index 3574844..a42e3fd 100644
--- a/bundles/org.eclipse.wst.jsdt.web.ui/src/org/eclipse/wst/jsdt/web/ui/internal/contentassist/JSDTCompletionProposal.java
+++ b/bundles/org.eclipse.wst.jsdt.web.ui/src/org/eclipse/wst/jsdt/web/ui/internal/contentassist/JSDTCompletionProposal.java
@@ -18,6 +18,7 @@
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.wst.jsdt.internal.ui.text.java.JavaCompletionProposal;
 import org.eclipse.wst.jsdt.internal.ui.text.java.LazyJavaCompletionProposal;
+import org.eclipse.wst.jsdt.internal.ui.text.java.LazyJavaTypeCompletionProposal;
 import org.eclipse.wst.jsdt.ui.text.java.IJavaCompletionProposal;
 
 /**
@@ -94,4 +95,11 @@
 	final public void setJavaCompletionProposal(ICompletionProposal javaCompletionProposal) {
 		fJavaCompletionProposal = javaCompletionProposal;
 	}
+	
+	protected boolean isValidPrefix(String prefix) {
+		if (this.fJavaCompletionProposal instanceof LazyJavaTypeCompletionProposal) {
+			return ((LazyJavaTypeCompletionProposal) this.fJavaCompletionProposal).isValidTypePrefix(prefix);
+		}
+		return super.isValidPrefix(prefix);
+	}
 }