diff --git a/tests/org.eclipse.jface.text.tests/src/org/eclipse/jface/text/tests/contentassist/AsyncContentAssistTest.java b/tests/org.eclipse.jface.text.tests/src/org/eclipse/jface/text/tests/contentassist/AsyncContentAssistTest.java
index 1d2370e40e1..6f293214561 100644
--- a/tests/org.eclipse.jface.text.tests/src/org/eclipse/jface/text/tests/contentassist/AsyncContentAssistTest.java
+++ b/tests/org.eclipse.jface.text.tests/src/org/eclipse/jface/text/tests/contentassist/AsyncContentAssistTest.java
@@ -17,6 +17,7 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeFalse;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -40,6 +41,8 @@
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 
+import org.eclipse.jface.util.Util;
+
 import org.eclipse.jface.text.Document;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.contentassist.ContentAssistant;
@@ -130,6 +133,7 @@ protected boolean condition() {
 
 	@Test
 	public void testCompleteActivationChar() {
+		assumeFalse("test fails on Windows, see https://github.com/eclipse-platform/eclipse.platform.ui/issues/890", Util.isWindows());
 		shell.setLayout(new FillLayout());
 		shell.setSize(500, 300);
 		SourceViewer viewer= new SourceViewer(shell, null, SWT.NONE);