diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Tree.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Tree.java
index 609596492e4..0eae7a0950c 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Tree.java	
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Tree.java	
@@ -182,28 +182,41 @@ TreeItem _getItem (long iter) {
 	int id = getId (iter, true);
 	if (items [id] != null) return items [id];
 	long path = GTK.gtk_tree_model_get_path (modelHandle, iter);
-	int depth = GTK.gtk_tree_path_get_depth (path);
-	int [] indices = new int [depth];
-	C.memmove (indices, GTK.gtk_tree_path_get_indices (path), 4*depth);
-	long parentIter = 0;
-	if (depth > 1) {
-		GTK.gtk_tree_path_up (path);
-		parentIter = OS.g_malloc (GTK.GtkTreeIter_sizeof ());
-		GTK.gtk_tree_model_get_iter (modelHandle, parentIter, path);
+	if (path == 0) error(SWT.ERROR_NO_HANDLES);
+	try {
+		int depth = GTK.gtk_tree_path_get_depth (path);
+		int [] indices = new int [depth];
+		C.memmove (indices, GTK.gtk_tree_path_get_indices (path), 4*depth);
+		long parentIter = 0;
+		try {
+			if (depth > 1) {
+				GTK.gtk_tree_path_up (path);
+				parentIter = OS.g_malloc (GTK.GtkTreeIter_sizeof ());
+				GTK.gtk_tree_model_get_iter (modelHandle, parentIter, path);
+			}
+			items [id] = new TreeItem (this, parentIter == 0 ? null : _getItem(parentIter), SWT.NONE, indices [indices.length -1], iter);
+		} finally {
+			if (parentIter != 0) OS.g_free (parentIter);
+		}
+	} finally {
+		GTK.gtk_tree_path_free (path);
 	}
-	items [id] = new TreeItem (this, parentIter == 0 ? null : _getItem(parentIter), SWT.NONE, indices [indices.length -1], false);
-	GTK.gtk_tree_path_free (path);
-	if (parentIter != 0) OS.g_free (parentIter);
 	return items [id];
 }
 
 TreeItem _getItem (TreeItem parentItem, int index) {
 	long iter = OS.g_malloc (GTK.GtkTreeIter_sizeof ());
-	GTK.gtk_tree_model_iter_nth_child(modelHandle, iter, parentItem == null ? 0 : parentItem.handle, index);
-	int id = getId (iter, true);
-	OS.g_free (iter);
-	if (items [id] != null) return items [id];
-	return items [id] = new TreeItem (this, parentItem, SWT.NONE, index, false);
+	try {
+		GTK.gtk_tree_model_iter_nth_child(modelHandle, iter, parentItem == null ? 0 : parentItem.handle, index);
+		int id = getId(iter, true);
+		if (items[id] != null)
+			return items[id];
+		TreeItem result = items[id] = new TreeItem(this, parentItem, SWT.NONE, index, iter);
+		assert verifyItem(result);
+		return result;
+	} finally {
+		OS.g_free(iter);
+	}
 }
 
 void reallocateIds(int newSize) {
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TreeItem.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TreeItem.java
index fc27f28dc54..43fca25264f 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TreeItem.java	
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TreeItem.java	
@@ -75,7 +75,7 @@ public class TreeItem extends Item {
  * @see Widget#getStyle
  */
 public TreeItem (Tree parent, int style) {
-	this (checkNull (parent), null, style, -1, true);
+	this (checkNull (parent), null, style, -1, 0);
 }
 
 /**
@@ -108,7 +108,7 @@ public TreeItem (Tree parent, int style) {
  * @see Tree#setRedraw
  */
 public TreeItem (Tree parent, int style, int index) {
-	this (checkNull (parent), null, style, checkIndex (index), true);
+	this (checkNull (parent), null, style, checkIndex (index), 0);
 }
 
 /**
@@ -134,7 +134,7 @@ public TreeItem (Tree parent, int style, int index) {
  * @see Widget#getStyle
  */
 public TreeItem (TreeItem parentItem, int style) {
-	this (checkNull (parentItem).parent, parentItem, style, -1, true);
+	this (checkNull (parentItem).parent, parentItem, style, -1, 0);
 }
 
 /**
@@ -163,10 +163,10 @@ public TreeItem (TreeItem parentItem, int style) {
  * @see Tree#setRedraw
  */
 public TreeItem (TreeItem parentItem, int style, int index) {
-	this (checkNull (parentItem).parent, parentItem, style, checkIndex (index), true);
+	this (checkNull (parentItem).parent, parentItem, style, checkIndex (index), 0);
 }
 
-TreeItem (Tree parent, TreeItem parentItem, int style, int index, boolean create) {
+TreeItem (Tree parent, TreeItem parentItem, int style, int index, long itemIter) {
 	super (parent, style);
 	this.parent = parent;
 	this.parentItem = parentItem;
@@ -175,7 +175,7 @@ public TreeItem (TreeItem parentItem, int style, int index) {
 		if (index < 0) {
 			index = parentItem.items.size();
 		}
-		if (create) {
+		if (itemIter == 0) {
 			ensureSizeAtLeast(parentItem.items, index);
 			parentItem.items.add(index, this);
 		} else {
@@ -187,11 +187,12 @@ public TreeItem (TreeItem parentItem, int style, int index) {
 			}
 		}
 	}
-	if (create) {
+	if (itemIter == 0) {
 		parent.createItem (this, parentItemHandle, index);
 	} else {
 		handle = OS.g_malloc (GTK.GtkTreeIter_sizeof ());
-		GTK.gtk_tree_model_iter_nth_child (parent.modelHandle, handle, parentItemHandle, index);
+		if (handle == 0) error(SWT.ERROR_NO_HANDLES);
+		C.memmove(handle, itemIter, GTK.GtkTreeIter_sizeof ());
 	}
 }
 
@@ -1140,30 +1141,24 @@ public void removeAll () {
 	checkWidget ();
 	parent.setRedraw(false);
 	try {
-		for (TreeItem item: List.copyOf(items) ) {
-			item.dispose();
+		for (TreeItem item: new ArrayList<>(items) ) {
+			if (item != null) {
+				item.dispose();
+			}
 		}
-		assert items.isEmpty() : "Children should remove theselves from parent";
+		items.clear();
 
 		long modelHandle = parent.modelHandle;
 		int length = GTK.gtk_tree_model_iter_n_children (modelHandle, handle);
-		assert length == 0 : "No GTK children should be left untrsacked";
 		if (length == 0) return;
 		long iter = OS.g_malloc (GTK.GtkTreeIter_sizeof ());
 		if (iter == 0) error (SWT.ERROR_NO_HANDLES);
 		try {
 			long selection = GTK.gtk_tree_view_get_selection (parent.handle);
-			int [] value = new int [1];
 			while (GTK.gtk_tree_model_iter_children (modelHandle, iter, handle)) {
-				GTK.gtk_tree_model_get (modelHandle, iter, Tree.ID_COLUMN, value, -1);
-				TreeItem item = value [0] != -1 ? parent.items [value [0]] : null;
-				if (item != null && !item.isDisposed ()) {
-					item.dispose ();
-				} else {
-					OS.g_signal_handlers_block_matched (selection, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, CHANGED);
-					GTK.gtk_tree_store_remove (modelHandle, iter);
-					OS.g_signal_handlers_unblock_matched (selection, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, CHANGED);
-				}
+				OS.g_signal_handlers_block_matched (selection, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, CHANGED);
+				GTK.gtk_tree_store_remove (modelHandle, iter);
+				OS.g_signal_handlers_unblock_matched (selection, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, CHANGED);
 			}
 		} finally {
 			OS.g_free (iter);