Bug 543746 - fixed NPE after control dispose

Change-Id: If7c4590ab46d5fb8371005c1e7933dead8ef90eb
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
diff --git a/bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/helpers/EmptyWorkspaceHelper.java b/bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/helpers/EmptyWorkspaceHelper.java
index fc6f331..dec8c0d 100644
--- a/bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/helpers/EmptyWorkspaceHelper.java
+++ b/bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/helpers/EmptyWorkspaceHelper.java
@@ -276,7 +276,7 @@
 	};
 
 	private boolean switchTopControl() {
-		if (control.isDisposed() || emptyArea.isDisposed()) {
+		if (control == null || control.isDisposed() || emptyArea == null || emptyArea.isDisposed()) {
 			return false;
 		}
 		Control oldTop = layout.topControl;