diff --git a/ua/org.eclipse.help.ui/META-INF/MANIFEST.MF b/ua/org.eclipse.help.ui/META-INF/MANIFEST.MF
index aaac5dfae17..56ae7855043 100644
--- a/ua/org.eclipse.help.ui/META-INF/MANIFEST.MF
+++ b/ua/org.eclipse.help.ui/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %help_system_plugin_name
 Bundle-SymbolicName: org.eclipse.help.ui; singleton:=true
-Bundle-Version: 4.8.0.qualifier
+Bundle-Version: 4.8.100.qualifier
 Bundle-Activator: org.eclipse.help.ui.internal.HelpUIPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
diff --git a/ua/org.eclipse.help.ui/src/org/eclipse/help/ui/internal/browser/embedded/EmbeddedBrowser.java b/ua/org.eclipse.help.ui/src/org/eclipse/help/ui/internal/browser/embedded/EmbeddedBrowser.java
index 639abb8bbf1..9bf2bc93cd9 100644
--- a/ua/org.eclipse.help.ui/src/org/eclipse/help/ui/internal/browser/embedded/EmbeddedBrowser.java
+++ b/ua/org.eclipse.help.ui/src/org/eclipse/help/ui/internal/browser/embedded/EmbeddedBrowser.java
@@ -36,6 +36,7 @@
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.browser.Browser;
+import org.eclipse.swt.browser.BrowserFunction;
 import org.eclipse.swt.browser.LocationAdapter;
 import org.eclipse.swt.browser.LocationEvent;
 import org.eclipse.swt.browser.LocationListener;
@@ -166,16 +167,13 @@ public void controlResized(ControlEvent e) {
 		shell.open();
 		//browser.setUrl("about:blank");
 
+		addNeedModalBrowserFunction(browser);
+		addResetNeedModalLocationListener(browser);
+
 		browser.addLocationListener(new LocationAdapter() {
 
 			@Override
 			public void changing(LocationEvent e) {
-				// hack to know when help webapp needs modal window
-				modalRequestTime = 0;
-				if (e.location != null
-						&& e.location.startsWith("javascript://needModal")) { //$NON-NLS-1$
-					modalRequestTime = System.currentTimeMillis();
-				}
 				if (!e.doit && e.location != null
 						&& e.location.startsWith("https://")) { //$NON-NLS-1$
 					try {
@@ -211,19 +209,33 @@ public EmbeddedBrowser(WindowEvent event, Shell parent) {
 		initialize(browser);
 		event.browser = browser;
 
-		browser.addLocationListener(new LocationAdapter() {
+		addNeedModalBrowserFunction(browser);
+		addResetNeedModalLocationListener(browser);
+	}
 
-			@Override
-			public void changing(LocationEvent e) {
-				// hack to know when help webapp needs modal window
-				modalRequestTime = 0;
-				if (e.location != null
-						&& e.location.startsWith("javascript://needModal")) { //$NON-NLS-1$
+	// hack to know when help webapp needs modal window
+	// use a browser function to be more robust
+	// see also https://github.com/eclipse-platform/eclipse.platform.swt/issues/2006
+	private void addNeedModalBrowserFunction(Browser browser) {
+		browser.getDisplay().asyncExec(() -> {
+			if (browser.isDisposed()) {
+				return;
+			}
+			new BrowserFunction(browser, "swtHintNeedModalPopup") { //$NON-NLS-1$
+				@Override
+				public Object function(Object[] arguments) {
+					super.function(arguments);
 					modalRequestTime = System.currentTimeMillis();
+					return null;
 				}
-			}
+			};
 		});
 	}
+
+	private void addResetNeedModalLocationListener(Browser browser) {
+		LocationListener.changingAdapter(e -> modalRequestTime = 0);
+	}
+
 	private static void initializeShell(Shell s) {
 		s.setText(initialTitle);
 		final Image[] shellImages = createImages();
diff --git a/ua/org.eclipse.help.webapp/advanced/navActions.js b/ua/org.eclipse.help.webapp/advanced/navActions.js
index f864cb5728d..5e8d340a4f5 100644
--- a/ua/org.eclipse.help.webapp/advanced/navActions.js
+++ b/ua/org.eclipse.help.webapp/advanced/navActions.js
@@ -193,7 +193,7 @@ function quickSearch(quickSearchType, errorMsg) {		//search this topic and all s
 		}		
 		// move the dialog just a bit higher than the middle
 		if (t-50 > 0) t = t-50;
-	  	window.location="javascript://needModal";  
+		if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	  	// Defect 593 ends
 
 		var quickSearchWindow = window.open("quickSearch.jsp" + parameters, "QuickSearch", "location=no, status=no,resizable=yes,height="+h+",width="+w +",left="+l+",top="+t);		
diff --git a/ua/org.eclipse.help.webapp/advanced/searchScoped.jsp b/ua/org.eclipse.help.webapp/advanced/searchScoped.jsp
index 8c629a23ea7..d30337a11a9 100644
--- a/ua/org.eclipse.help.webapp/advanced/searchScoped.jsp
+++ b/ua/org.eclipse.help.webapp/advanced/searchScoped.jsp
@@ -183,7 +183,7 @@ if (data.isIE()){
 	// move the dialog just a bit higher than the middle
 	if (t-50 > 0) t = t-50;
 	
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	advancedDialog = window.open("workingSetManager.jsp?workingSet="+encodeURIComponent(workingSet), "advancedDialog", "resizable=yes,height="+h+",width="+w+",left="+l+",top="+t );
 	advancedDialog.focus(); 
 }
diff --git a/ua/org.eclipse.help.webapp/advanced/searchSimple.jsp b/ua/org.eclipse.help.webapp/advanced/searchSimple.jsp
index 9d7e80a73ec..99fa8c33809 100644
--- a/ua/org.eclipse.help.webapp/advanced/searchSimple.jsp
+++ b/ua/org.eclipse.help.webapp/advanced/searchSimple.jsp
@@ -144,7 +144,7 @@ function saveSelectedBooks(books)
 
 function openAdvanced()
 {
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	advancedDialog = window.open("advanced.jsp?searchWord="+encodeURIComponent(document.getElementById("searchWord").value), "advancedDialog", "resizable=yes,height="+h+",width="+w );
 	advancedDialog.focus(); 
 }
diff --git a/ua/org.eclipse.help.webapp/advanced/views.jsp b/ua/org.eclipse.help.webapp/advanced/views.jsp
index 55c35c8cbd2..a64b1118450 100644
--- a/ua/org.eclipse.help.webapp/advanced/views.jsp
+++ b/ua/org.eclipse.help.webapp/advanced/views.jsp
@@ -89,7 +89,7 @@ if (data.isIE()){
 	// move the dialog just a bit higher than the middle
 	if (t-50 > 0) t = t-50;
 	
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	confirmShowAllDialog = window.open("confirmShowAll.jsp", "confirmShowAllDialog", "resizable=no,height="+h+",width="+w+",left="+l+",top="+t );
 	confirmShowAllDialog.focus(); 
 }
@@ -112,7 +112,7 @@ if (data.isIE()){
 	// move the dialog just a bit higher than the middle
 	if (t-50 > 0) t = t-50;
 	
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	selectScopeDialog = window.open("selectScope.jsp", "selectScopeDialog", "resizable=no,height="+h+",width="+w+",left="+l+",top="+t );
 	selectScopeDialog.focus(); 
 }
diff --git a/ua/org.eclipse.help.webapp/advanced/workingSetManager.jsp b/ua/org.eclipse.help.webapp/advanced/workingSetManager.jsp
index 2514d8d6951..2d04497d7f9 100644
--- a/ua/org.eclipse.help.webapp/advanced/workingSetManager.jsp
+++ b/ua/org.eclipse.help.webapp/advanced/workingSetManager.jsp
@@ -224,7 +224,7 @@ function newWorkingSet() {
 	%>
 	// move the dialog just a bit higher than the middle
 	if (t-50 > 0) t = t-50;
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	workingSetDialog = window.open("workingSet.jsp?operation=add&workingSet="+encodeURIComponent(getWorkingSet()), "workingSetDialog", "resizable=yes,height="+h+",width="+w +",left="+l+",top="+t);
 	workingSetDialog.focus(); 
 }
@@ -247,7 +247,7 @@ function editWorkingSet() {
 	// move the dialog just a bit higher than the middle
 	if (t-50 > 0) t = t-50;
 		
-	window.location="javascript://needModal";
+	if (typeof top.swtHintNeedModalPopup === "function") top.swtHintNeedModalPopup();
 	workingSetDialog = window.open("workingSet.jsp?operation=edit&workingSet="+encodeURIComponent(getWorkingSet()), "workingSetDialog", "resizable=no,height="+h+",width="+w+",left="+l+",top="+t );
 	workingSetDialog.focus(); 
 }