fix: block F5/Refresh in chat webview to prevent blank screen

plugin/src/software/aws/toolkits/eclipse/amazonq/views/AmazonQChatWebview.java

@@ -62,6 +62,11 @@ public void completed(final ProgressEvent event) {
             });
 
             webViewAssetProvider.setContent(browser);
+
+            // Block F5/Refresh - the webview uses setText() with no backing URL,
+            // so browser refresh navigates to about:blank or file:/// causing a blank screen.
+            browser.addLocationListener(new RefreshBlockingLocationListener());
+            browser.addKeyListener(new RefreshBlockingKeyListener());
         }
 
         super.setupView(parent);

plugin/src/software/aws/toolkits/eclipse/amazonq/views/RefreshBlockingKeyListener.java

@@ -0,0 +1,31 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.views;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.KeyAdapter;
+import org.eclipse.swt.events.KeyEvent;
+
+/**
+ * Blocks F5 keypress to prevent browser refresh in the chat webview.
+ * The webview uses setText() with no backing URL, so F5 would navigate
+ * to about:blank, wiping the UI.
+ */
+final class RefreshBlockingKeyListener extends KeyAdapter {
+
+    @Override
+    public void keyPressed(final KeyEvent e) {
+        if (shouldBlockKey(e.keyCode)) {
+            e.doit = false;
+        }
+    }
+
+    /**
+     * Determines whether the given key code should be blocked.
+     * Package-private for testability.
+     */
+    static boolean shouldBlockKey(final int keyCode) {
+        return keyCode == SWT.F5;
+    }
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/views/RefreshBlockingLocationListener.java

@@ -0,0 +1,38 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.views;
+
+import org.eclipse.swt.browser.LocationAdapter;
+import org.eclipse.swt.browser.LocationEvent;
+
+/**
+ * Blocks browser navigation to prevent the chat webview from going blank on
+ * refresh. The webview uses setText() with no backing URL, so any refresh or
+ * navigation attempt will leave the rendered content. On different platforms,
+ * refresh may navigate to about:blank (Windows/Linux) or file:/// (macOS WebKit).
+ * This listener blocks all navigation since the webview should never navigate away.
+ */
+final class RefreshBlockingLocationListener extends LocationAdapter {
+
+    @Override
+    public void changing(final LocationEvent event) {
+        if (shouldBlockNavigation(event.location)) {
+            event.doit = false;
+        }
+    }
+
+    /**
+     * Determines whether navigation to the given location should be blocked.
+     * Blocks about:blank and file:// URLs which are triggered by refresh on
+     * different platforms. The webview content is set via setText() and should
+     * never navigate to any URL.
+     * Package-private for testability.
+     */
+    static boolean shouldBlockNavigation(final String location) {
+        if (location == null || location.isEmpty()) {
+            return false;
+        }
+        return "about:blank".equals(location) || location.startsWith("file:");
+    }
+}

plugin/tst/software/aws/toolkits/eclipse/amazonq/views/RefreshBlockingKeyListenerTest.java

@@ -0,0 +1,49 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.views;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.eclipse.swt.SWT;
+import org.junit.jupiter.api.Test;
+
+public final class RefreshBlockingKeyListenerTest {
+
+    @Test
+    void testBlocksF5KeyPress() {
+        assertTrue(RefreshBlockingKeyListener.shouldBlockKey(SWT.F5),
+                "F5 keypress should be blocked");
+    }
+
+    @Test
+    void testAllowsF4KeyPress() {
+        assertFalse(RefreshBlockingKeyListener.shouldBlockKey(SWT.F4),
+                "F4 keypress should not be blocked");
+    }
+
+    @Test
+    void testAllowsF6KeyPress() {
+        assertFalse(RefreshBlockingKeyListener.shouldBlockKey(SWT.F6),
+                "F6 keypress should not be blocked");
+    }
+
+    @Test
+    void testAllowsEnterKey() {
+        assertFalse(RefreshBlockingKeyListener.shouldBlockKey(SWT.CR),
+                "Enter key should not be blocked");
+    }
+
+    @Test
+    void testAllowsRegularCharacterKey() {
+        assertFalse(RefreshBlockingKeyListener.shouldBlockKey('a'),
+                "Regular character keys should not be blocked");
+    }
+
+    @Test
+    void testAllowsEscapeKey() {
+        assertFalse(RefreshBlockingKeyListener.shouldBlockKey(SWT.ESC),
+                "Escape key should not be blocked");
+    }
+}

plugin/tst/software/aws/toolkits/eclipse/amazonq/views/RefreshBlockingLocationListenerTest.java

@@ -0,0 +1,48 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.views;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public final class RefreshBlockingLocationListenerTest {
+
+    @Test
+    void testBlocksNavigationToAboutBlank() {
+        assertTrue(RefreshBlockingLocationListener.shouldBlockNavigation("about:blank"),
+                "Navigation to about:blank should be blocked");
+    }
+
+    @Test
+    void testBlocksNavigationToFileProtocol() {
+        assertTrue(RefreshBlockingLocationListener.shouldBlockNavigation("file:///"),
+                "Navigation to file:/// should be blocked (macOS WebKit reload)");
+    }
+
+    @Test
+    void testBlocksNavigationToFileProtocolWithPath() {
+        assertTrue(RefreshBlockingLocationListener.shouldBlockNavigation("file:///tmp/test.html"),
+                "Navigation to file:// URLs should be blocked");
+    }
+
+    @Test
+    void testAllowsNavigationToHttpsUrl() {
+        assertFalse(RefreshBlockingLocationListener.shouldBlockNavigation("https://example.com"),
+                "Navigation to HTTPS URLs should be allowed");
+    }
+
+    @Test
+    void testAllowsNavigationWhenLocationIsNull() {
+        assertFalse(RefreshBlockingLocationListener.shouldBlockNavigation(null),
+                "Navigation should be allowed when location is null");
+    }
+
+    @Test
+    void testAllowsNavigationToEmptyString() {
+        assertFalse(RefreshBlockingLocationListener.shouldBlockNavigation(""),
+                "Navigation should be allowed when location is empty");
+    }
+}