Process events until parent shell is activated

It may take some event cycles before the parent shell that
is getting focus/activation back gets the notification.
Therefore wait until the Activate listener is called

Author: jonahgraham

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Shell.java

@@ -26,6 +26,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
@@ -43,6 +44,7 @@
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Text;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;
 
 /**
@@ -652,21 +654,33 @@ public void test_setBoundsLorg_eclipse_swt_graphics_Rectangle() {
  * Regression test for Bug 436841 - [GTK3] FocusOut/In and Activate/Deactivate
  * events when opening context menu. Only applicable on GTK x11.
  */
-@Test
-public void test_activateEventSend() {
+@RepeatedTest(value = 1000)
+public void test_activateEventSend() throws InterruptedException {
 	if (SwtTestUtil.isGTK && SwtTestUtil.isX11) {
+		AtomicBoolean activateCalled = new AtomicBoolean();
+		AtomicBoolean deactivateCalled = new AtomicBoolean();
 		Shell testShell = new Shell(shell, SWT.SHELL_TRIM);
 		testShell.addListener(SWT.Activate, e -> {
-			listenerCalled = true;
+			activateCalled.set(true);
+			});
+		testShell.addListener(SWT.Deactivate, e -> {
+			deactivateCalled.set(true);
 			});
+		activateCalled.set(false);
 		testShell.open();
+		SwtTestUtil.processEvents(10000, () -> activateCalled.get());
+		assertTrue(activateCalled.get());
 		int[] styles = {SWT.ON_TOP, SWT.APPLICATION_MODAL, SWT.PRIMARY_MODAL, SWT.SYSTEM_MODAL, SWT.NO_TRIM, SWT.BORDER, SWT.SHELL_TRIM};
 		for (int style : styles) {
+			deactivateCalled.set(false);
 			Shell childShell = new Shell(testShell, style);
-			listenerCalled = false;
 			childShell.open();
+			SwtTestUtil.processEvents(10000, () -> deactivateCalled.get());
+			assertTrue(deactivateCalled.get());
+			activateCalled.set(false);
 			childShell.dispose();
-			assertTrue(listenerCalled);
+			SwtTestUtil.processEvents(10000, () -> activateCalled.get());
+			assertTrue(activateCalled.get());
 		}
 	}
 }