Fix context menu for Edge in Windows (#77)

* Add browser function that fires on context menu request
* Add example for custom context menu in workflow diagram

Fixes eclipse-glsp/glsp#978
Fixes eclipse-glsp/glsp#969

Contributed on behalf of STMicroelectronics

Author: planger

server/example/org.eclipse.glsp.ide.workflow.editor/plugin.xml

@@ -26,7 +26,7 @@
             allPopups="false"
             locationURI="popup:org.eclipse.glsp.workflow.editor">
          <separator
-               name="org.eclipse.glsp.integration.workflow.editor.edit_start">
+               name="org.eclipse.glsp.integration.workflow.editor.edit_start" visible="true">
          </separator>
          <command
                commandId="org.eclipse.ui.edit.copy"
@@ -43,6 +43,13 @@
          <separator
                name="org.eclipse.glsp.integration.workflow.editor.edit_end">
          </separator>
+         <separator
+               name="org.eclipse.glsp.integration.workflow.editor.navigate_start" visible="true">
+         </separator>
+         <command
+              commandId="org.eclipse.glsp.ide.workflow.editor.navigate.next-node"
+              style="push">
+        </command>
          <dynamic
                class="org.eclipse.glsp.ide.editor.ui.GLSPDynamicContribution"
                id="org.eclipse.glsp.ide.editor.actionprovider">

server/plugins/org.eclipse.glsp.ide.editor/src/org/eclipse/glsp/ide/editor/ui/BrowserContextMenuInstaller.java

@@ -0,0 +1,48 @@
+/********************************************************************************
+ * Copyright (c) 2023 EclipseSource and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * https://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ ********************************************************************************/
+package org.eclipse.glsp.ide.editor.ui;
+
+import java.util.Optional;
+
+import org.eclipse.swt.browser.Browser;
+import org.eclipse.swt.browser.BrowserFunction;
+
+public class BrowserContextMenuInstaller implements BrowserFunctionInstaller {
+
+   private static final String FUNCTION_NAME = "requestContextMenu";
+   private static final String FUNCTION_INSTALLER = "document.addEventListener(\"contextmenu\", e => { requestContextMenu(); e.preventDefault(); });";
+
+   @Override
+   public Optional<BrowserFunction> install(final Browser browser) {
+      BrowserFunction browserFunction = new BrowserFunction(browser, FUNCTION_NAME) {
+         @Override
+         public Object function(final Object[] arguments) {
+            browser.getDisplay().asyncExec(() -> requestContextMenu(browser));
+            return null;
+         }
+      };
+      browser.execute(FUNCTION_INSTALLER);
+      return Optional.of(browserFunction);
+   }
+
+   protected void requestContextMenu(final Browser browser) {
+      if (browser.isDisposed()) {
+         return;
+      }
+      browser.getMenu().setEnabled(true);
+      browser.getMenu().setVisible(true);
+   }
+}

server/plugins/org.eclipse.glsp.ide.editor/src/org/eclipse/glsp/ide/editor/ui/GLSPDiagramEditor.java

@@ -361,9 +361,8 @@ protected void syncMarkers(final GModelState modelState) {
          .ifPresent(toDispose::add);
    }
 
-   @SuppressWarnings("deprecation")
    protected Browser createBrowser(final Composite parent) {
-      Browser browser = new FocusAwareBrowser(parent, SWT.NO_SCROLL | SWT.EDGE | SWT.CHROMIUM);
+      Browser browser = new FocusAwareBrowser(parent, SWT.NO_SCROLL | SWT.EDGE);
       browser.setLayoutData(new GridData(GridData.FILL, GridData.FILL, true, true));
       toDispose.add(browser::dispose);
       return browser;
@@ -405,6 +404,7 @@ protected void installBrowserFunctions() {
       // browser functions are automatically disposed with the browser
       new BrowserKeyBindingForwarderInstaller(getSite()).install(browser);
       new BrowserFocusControlInstaller().install(browser);
+      new BrowserContextMenuInstaller().install(browser);
    }
 
    protected String getBaseUrl() { return "diagram.html"; }