Fix StickyScrollingHandlerTest.testThrottledExecution on Mac

The unit test StickyScrollingHandlerTest.testThrottledExecution was failing in the I build on MacOS. With this change, the test should run again.

Fixes eclipse-platform#2190

tests/org.eclipse.ui.editors.tests/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyScrollingHandlerTest.java

@@ -28,6 +28,7 @@
 import java.util.List;
 import java.util.StringJoiner;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -75,6 +76,11 @@ public void setup() {
 		stickyScrollingHandler = new StickyScrollingHandler(sourceViewer, ruler, store, linesProvider);
 	}
 
+	@After
+	public void teardown() {
+		shell.dispose();
+	}
+
 	@Test
 	public void testShowStickyLines() {
 		when(linesProvider.get(100, sourceViewer)).thenReturn(List.of(new StickyLine("line 10", 9)));
@@ -129,13 +135,19 @@ public void testPreferencesUpdated() {
 	@Test
 	public void testThrottledExecution() throws InterruptedException {
 		when(linesProvider.get(100, sourceViewer)).thenReturn(List.of(new StickyLine("line 10", 9)));
+		when(linesProvider.get(200, sourceViewer)).thenReturn(List.of(new StickyLine("line 10", 9)));
+		when(linesProvider.get(300, sourceViewer)).thenReturn(List.of(new StickyLine("line 10", 9)));
+		when(linesProvider.get(400, sourceViewer)).thenReturn(List.of(new StickyLine("line 10", 9)));
 
 		stickyScrollingHandler.viewportChanged(100);
+		waitInUi(10);
 		stickyScrollingHandler.viewportChanged(200);
+		waitInUi(10);
 		stickyScrollingHandler.viewportChanged(300);
+		waitInUi(10);
 		stickyScrollingHandler.viewportChanged(400);
 
-		waitInUi(200);
+		waitInUi(300);
 
 		// Call to lines provider should be throttled
 		verify(linesProvider, times(1)).get(100, sourceViewer);