diff --git a/tests/org.eclipse.ui.tests.harness/src/org/eclipse/ui/tests/harness/util/UITestCase.java b/tests/org.eclipse.ui.tests.harness/src/org/eclipse/ui/tests/harness/util/UITestCase.java
index 4ebc7ed06f2..436b0f884bc 100644
--- a/tests/org.eclipse.ui.tests.harness/src/org/eclipse/ui/tests/harness/util/UITestCase.java
+++ b/tests/org.eclipse.ui.tests.harness/src/org/eclipse/ui/tests/harness/util/UITestCase.java
@@ -21,6 +21,7 @@
 import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.eclipse.core.resources.ResourcesPlugin;
@@ -30,7 +31,6 @@
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.preference.PreferenceMemento;
-import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.ShellEvent;
 import org.eclipse.swt.events.ShellListener;
 import org.eclipse.swt.widgets.Display;
@@ -75,6 +75,7 @@ public static IAdaptable getPageInput() {
 	private final CloseTestWindowsRule closeTestWindows = new CloseTestWindowsRule();
 
 	protected IWorkbench fWorkbench;
+	private Set<Shell> preExistingShells;
 
 	/** Preference helper to restore changed preference values after test run. */
 	private final PreferenceMemento prefMemento = new PreferenceMemento();
@@ -180,6 +181,7 @@ public final void setUp() throws Exception {
 		super.setUp();
 		closeTestWindows.before();
 		fWorkbench = PlatformUI.getWorkbench();
+		this.preExistingShells = Set.of(fWorkbench.getDisplay().getShells());
 		String name = runningTest != null ? runningTest : this.getName();
 		trace(TestRunLogUtil.formatTestStartMessage(name));
 		doSetUp();
@@ -212,18 +214,17 @@ public final void tearDown() throws Exception {
 		trace(TestRunLogUtil.formatTestFinishedMessage(name));
 		prefMemento.resetPreferences();
 		doTearDown();
-		fWorkbench = null;
 
-		// Check for modal shell leak.
+		// Check for shell leak.
 		List<String> leakedModalShellTitles = new ArrayList<>();
-		Shell[] shells = PlatformUI.getWorkbench().getDisplay().getShells();
+		Shell[] shells = fWorkbench.getDisplay().getShells();
 		for (Shell shell : shells) {
-			if (!shell.isDisposed() && shell.isVisible()
-					&& (shell.getStyle() & (SWT.APPLICATION_MODAL | SWT.PRIMARY_MODAL | SWT.SYSTEM_MODAL)) != 0) {
+			if (!shell.isDisposed() && !preExistingShells.contains(shell)) {
 				leakedModalShellTitles.add(shell.getText());
 				shell.close();
 			}
 		}
+		fWorkbench = null;
 		assertEquals("Test leaked modal shell: [" + String.join(", ", leakedModalShellTitles) + "]", 0,
 				leakedModalShellTitles.size());
 	}
diff --git a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingArchiveProjectFilterTest.java b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingArchiveProjectFilterTest.java
index 1aff6631812..5132ead15f5 100644
--- a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingArchiveProjectFilterTest.java	
+++ b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingArchiveProjectFilterTest.java	
@@ -40,13 +40,13 @@
 import org.eclipse.ui.IPageLayout;
 import org.eclipse.ui.IViewPart;
 import org.eclipse.ui.IWorkbenchPage;
+import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.dialogs.ImportExportWizard;
 import org.eclipse.ui.internal.wizards.datatransfer.WizardProjectsImportPage;
 import org.eclipse.ui.internal.wizards.datatransfer.WizardProjectsImportPage.ProjectRecord;
 import org.eclipse.ui.navigator.resources.ProjectExplorer;
 import org.eclipse.ui.tests.TestPlugin;
-import org.eclipse.ui.tests.harness.util.DialogCheck;
 import org.eclipse.ui.tests.harness.util.EmptyPerspective;
 import org.eclipse.ui.tests.harness.util.FileUtil;
 import org.eclipse.ui.tests.harness.util.UITestCase;
@@ -66,6 +66,10 @@ public ImportExistingArchiveProjectFilterTest() {
 
 	@Override
 	protected void doTearDown() throws Exception {
+		if (dialog != null) {
+			dialog.close();
+			dialog = null;
+		}
 		IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();
 		IProject[] projects = wsRoot.getProjects();
 		for (int i = projects.length - 1; i >= 0; i--) {
@@ -158,6 +162,7 @@ private void processElementAndChildren(Object element, ITreeContentProvider cont
 		}
 	}
 
+	private WizardDialog dialog;
 	public WizardProjectsImportPage getNewWizard() {
 		ImportExportWizard wizard = new ImportExportWizard(ImportExportWizard.IMPORT);
 		wizard.init(getWorkbench(), null);
@@ -173,7 +178,10 @@ public WizardProjectsImportPage getNewWizard() {
 
 		Shell shell = getShell();
 
-		WizardDialog dialog = new WizardDialog(shell, wizard);
+		if (dialog != null) {
+			dialog.close();
+		}
+		dialog = new WizardDialog(shell, wizard);
 		dialog.create();
 		dialog.getShell().setSize(Math.max(100, dialog.getShell().getSize().x), 100);
 
@@ -185,6 +193,6 @@ public WizardProjectsImportPage getNewWizard() {
 	}
 
 	private Shell getShell() {
-		return DialogCheck.getShell();
+		return PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
 	}
 }
diff --git a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingProjectsWizardTest.java b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingProjectsWizardTest.java
index 4149e8089b6..80b17938d83 100644
--- a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingProjectsWizardTest.java	
+++ b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/datatransfer/ImportExistingProjectsWizardTest.java	
@@ -56,7 +56,6 @@
 import org.eclipse.ui.internal.wizards.datatransfer.WizardProjectsImportPage.ProjectRecord;
 import org.eclipse.ui.tests.TestPlugin;
 import org.eclipse.ui.tests.datatransfer.ImportTestUtils.TestBuilder;
-import org.eclipse.ui.tests.harness.util.DialogCheck;
 import org.eclipse.ui.tests.harness.util.FileUtil;
 import org.eclipse.ui.tests.harness.util.UITestCase;
 import org.eclipse.ui.wizards.datatransfer.ExternalProjectImportWizard;
@@ -86,6 +85,8 @@ public class ImportExistingProjectsWizardTest extends UITestCase {
 
 	private String zipLocation = null;
 
+	private WizardDialog dialog;
+
 	private boolean originalRefreshSetting;
 
 	public ImportExistingProjectsWizardTest() {
@@ -93,7 +94,7 @@ public ImportExistingProjectsWizardTest() {
 	}
 
 	private Shell getShell() {
-		return DialogCheck.getShell();
+		return PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
 	}
 
 	@Override
@@ -109,6 +110,11 @@ protected void doSetUp() throws Exception {
 
 	@Override
 	protected void doTearDown() throws Exception {
+		if (dialog != null) {
+			dialog.close();
+			dialog = null;
+		}
+
 		IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();
 		IProject[] projects = wsRoot.getProjects();
 		for (int i = projects.length - 1; i >= 0; i--) {
@@ -799,8 +805,6 @@ public void test14InitialValue() throws IOException, CoreException {
 			wpip = getExternalImportWizard(null);
 			selectedProjects = wpip.getProjectRecords();
 			assertEquals(0, selectedProjects.length);
-
-
 	}
 
 	@Test
@@ -900,7 +904,6 @@ private String copyZipLocation(String zipLocation) throws IOException {
 		return ImportTestUtils.copyZipLocation(zipLocation, ARCHIVE_HELLOWORLD);
 	}
 
-
 	private WizardProjectsImportPage getNewWizard() {
 		ImportExportWizard wizard = new ImportExportWizard(
 				ImportExportWizard.IMPORT);
@@ -920,7 +923,10 @@ private WizardProjectsImportPage getNewWizard() {
 
 		Shell shell = getShell();
 
-		WizardDialog dialog = new WizardDialog(shell, wizard);
+		if (dialog != null) {
+			dialog.close();
+		}
+		dialog = new WizardDialog(shell, wizard);
 		dialog.create();
 		dialog.getShell().setSize(Math.max(100, dialog.getShell().getSize().x),
 				100);
@@ -1176,7 +1182,10 @@ private WizardProjectsImportPage getExternalImportWizard(String initialPath) {
 		ExternalProjectImportWizard wizard = new ExternalProjectImportWizard(
 				initialPath);
 		wizard.init(getWorkbench(), null);
-		WizardDialog dialog = new WizardDialog(getShell(), wizard);
+		if (dialog != null) {
+			dialog.close();
+		}
+		dialog = new WizardDialog(getShell(), wizard);
 		dialog.create();
 
 		dialog.getShell().setSize(Math.max(100, dialog.getShell().getSize().x),
diff --git a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/markers/MarkerViewTests.java b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/markers/MarkerViewTests.java
index 77782ed8ef4..6efcc2e7a25 100644
--- a/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/markers/MarkerViewTests.java	
+++ b/tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/markers/MarkerViewTests.java	
@@ -46,9 +46,9 @@ public void testOpenView() {
 		IWorkbenchPage page = window.getActivePage();
 
 		try {
-			page.showView(IPageLayout.ID_BOOKMARKS);
-			page.showView(IPageLayout.ID_PROBLEM_VIEW);
-			page.showView(IPageLayout.ID_TASK_LIST);
+			page.hideView(page.showView(IPageLayout.ID_BOOKMARKS));
+			page.hideView(page.showView(IPageLayout.ID_PROBLEM_VIEW));
+			page.hideView(page.showView(IPageLayout.ID_TASK_LIST));
 		} catch (PartInitException e) {
 			assertTrue(e.getLocalizedMessage(), false);
 			return;