Welcome Page does not handle Editors Area correctly

fixes #3739

Author: N1k145

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/ViewIntroAdapterPart.java

@@ -20,12 +20,16 @@
 import org.eclipse.core.runtime.Status;
 import org.eclipse.e4.core.services.events.IEventBroker;
 import org.eclipse.e4.ui.model.application.ui.MUIElement;
+import org.eclipse.e4.ui.model.application.ui.advanced.MArea;
+import org.eclipse.e4.ui.model.application.ui.advanced.MPlaceholder;
 import org.eclipse.e4.ui.model.application.ui.basic.MPart;
 import org.eclipse.e4.ui.model.application.ui.basic.MPartStack;
 import org.eclipse.e4.ui.workbench.IPresentationEngine;
 import org.eclipse.e4.ui.workbench.UIEvents;
 import org.eclipse.e4.ui.workbench.UIEvents.EventTags;
+import org.eclipse.e4.ui.workbench.addons.minmax.MinMaxAddonUtil;
 import org.eclipse.swt.custom.BusyIndicator;
+import org.eclipse.swt.custom.CTabFolder;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
@@ -59,12 +63,20 @@ public final class ViewIntroAdapterPart extends ViewPart {
 		}
 
 		Object changedObj = event.getProperty(EventTags.ELEMENT);
-		if (!(changedObj instanceof MPartStack)) {
+		if (!(changedObj instanceof MPartStack) && !(changedObj instanceof MPlaceholder)) {
 			return;
 		}
 
-		if (changedObj != getIntroStack()) {
-			return;
+		MPartStack introStack = getIntroStack();
+		if (changedObj != introStack) {
+			MArea parentArea = MinMaxAddonUtil.getAreaFor(introStack);
+			if (parentArea != null && !(parentArea.getWidget() instanceof CTabFolder)) {
+				if (parentArea.getCurSharedRef() != changedObj) {
+					return;
+				}
+			} else {
+				return;
+			}
 		}
 
 		if (UIEvents.isADD(event)

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/WorkbenchIntroManager.java

@@ -21,10 +21,13 @@
 import org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler;
 import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;
 import org.eclipse.e4.ui.model.application.ui.MUIElement;
+import org.eclipse.e4.ui.model.application.ui.advanced.MArea;
 import org.eclipse.e4.ui.model.application.ui.advanced.MPlaceholder;
 import org.eclipse.e4.ui.model.application.ui.basic.MPart;
 import org.eclipse.e4.ui.model.application.ui.basic.MPartStack;
 import org.eclipse.e4.ui.workbench.IPresentationEngine;
+import org.eclipse.e4.ui.workbench.addons.minmax.MinMaxAddonUtil;
+import org.eclipse.swt.custom.CTabFolder;
 import org.eclipse.ui.IViewPart;
 import org.eclipse.ui.IViewReference;
 import org.eclipse.ui.IWorkbenchPage;
@@ -191,7 +194,7 @@ public void setIntroStandby(IIntroPart part, boolean standby) {
 			return;
 		}
 
-		MPartStack introStack = getIntroStack(viewIntroAdapterPart);
+		MUIElement introStack = getIntroStack(viewIntroAdapterPart);
 		if (introStack == null) {
 			return;
 		}
@@ -204,22 +207,26 @@ public void setIntroStandby(IIntroPart part, boolean standby) {
 		}
 	}
 
-	private MPartStack getIntroStack(ViewIntroAdapterPart introAdapter) {
+	private MUIElement getIntroStack(ViewIntroAdapterPart introAdapter) {
 		ViewSite site = (ViewSite) introAdapter.getViewSite();
 
 		MPart introModelPart = site.getModel();
 		if (introModelPart.getCurSharedRef() != null) {
 			MUIElement introPartParent = introModelPart.getCurSharedRef().getParent();
-			if (introPartParent instanceof MPartStack) {
-				return (MPartStack) introPartParent;
+			if (introPartParent instanceof MPartStack parentStack) {
+				MArea parentArea = MinMaxAddonUtil.getAreaFor(parentStack);
+				if (parentArea != null && !(parentArea.getWidget() instanceof CTabFolder)) {
+					return parentArea.getCurSharedRef();
+				}
+				return introPartParent;
 			}
 		}
 
 		return null;
 	}
 
 	private boolean isIntroMaximized(ViewIntroAdapterPart introAdapter) {
-		MPartStack introStack = getIntroStack(introAdapter);
+		MUIElement introStack = getIntroStack(introAdapter);
 		if (introStack == null) {
 			return false;
 		}