diff --git a/common/lc_model.cpp b/common/lc_model.cpp
index 52a5ada6..fb5a6f3a 100644
--- a/common/lc_model.cpp
+++ b/common/lc_model.cpp
@@ -2371,50 +2371,57 @@ void lcModel::RemoveFocusPieceFromGroup()
 
 void lcModel::ShowEditGroupsDialog()
 {
-	QMap<lcPiece*, lcGroup*> PieceParents;
-	QMap<lcGroup*, lcGroup*> GroupParents;
-
-	for (const std::unique_ptr<lcPiece>& Piece : mPieces)
-		PieceParents[Piece.get()] = Piece->GetGroup();
-
-	for (const std::unique_ptr<lcGroup>& Group : mGroups)
-		GroupParents[Group.get()] = Group->mGroup;
-
-	lcQEditGroupsDialog Dialog(gMainWindow, PieceParents, GroupParents, this);
+	lcQEditGroupsDialog Dialog(gMainWindow, this);
 
 	if (Dialog.exec() != QDialog::Accepted)
 		return;
-
-	bool Modified = Dialog.mNewGroups.isEmpty();
-
-	for (const std::unique_ptr<lcPiece>& Piece : mPieces)
+	
+	BeginActionSequence();
+	BeginObjectEditAction();
+	
+	std::function<void(const lcQEditGroupsDialog::GroupInfo&, lcGroup*)> UpdateGroups=[this, &UpdateGroups](const lcQEditGroupsDialog::GroupInfo& GroupInfo, lcGroup* ParentGroup)
 	{
-		lcGroup* ParentGroup = Dialog.mPieceParents.value(Piece.get());
-
-		if (ParentGroup != Piece->GetGroup())
+		lcGroup* Group = GroupInfo.Group;
+		
+		if (!Group)
 		{
-			Piece->SetGroup(ParentGroup);
-			Modified = true;
+			Group = new lcGroup();
+			mGroups.emplace_back(Group);
 		}
-	}
+		
+		Group->mName = GroupInfo.Name;
+		Group->mGroup = ParentGroup;
+		
+		for (const lcQEditGroupsDialog::GroupInfo& ChildGroupInfo : GroupInfo.ChildGroups)
+			UpdateGroups(ChildGroupInfo, Group);
+		
+		for (lcPiece* Piece : GroupInfo.ChildPieces)
+			Piece->SetGroup(Group);		
+	};
+	
+	lcQEditGroupsDialog::GroupInfo GroupInfo = Dialog.GetGroups();
+	
+	for (const lcQEditGroupsDialog::GroupInfo& ChildGroupInfo : GroupInfo.ChildGroups)
+		UpdateGroups(ChildGroupInfo, nullptr);
+	
+	for (lcPiece* Piece : GroupInfo.ChildPieces)
+		Piece->SetGroup(nullptr);
+	
+	RemoveEmptyGroups();
 
-	for (const std::unique_ptr<lcGroup>& Group : mGroups)
+	EndObjectEditAction();
+	
+	if (mActionSequence.empty())
 	{
-		lcGroup* ParentGroup = Dialog.mGroupParents.value(Group.get());
-
-		if (ParentGroup != Group->mGroup)
-		{
-			Group->mGroup = ParentGroup;
-			Modified = true;
-		}
+		DiscardActionSequence();
+		return;
 	}
+	
+	RecordClearSelectionAction();
+	
+	EndActionSequence(tr("Edit Groups"));
 
-	if (Modified)
-	{
-		DeselectAllObjects();
-		gMainWindow->UpdateSelectedObjects(true);
-		SaveCheckpoint(tr("Editing Groups"));
-	}
+	gMainWindow->UpdateSelectedObjects(true);
 }
 
 QString lcModel::GetGroupName(const QString& Prefix)
diff --git a/qt/lc_qeditgroupsdialog.cpp b/qt/lc_qeditgroupsdialog.cpp
index 1fb28e30..6ddd289f 100644
--- a/qt/lc_qeditgroupsdialog.cpp
+++ b/qt/lc_qeditgroupsdialog.cpp
@@ -1,28 +1,52 @@
 #include "lc_global.h"
 #include "lc_qeditgroupsdialog.h"
 #include "ui_lc_qeditgroupsdialog.h"
-#include "lc_application.h"
 #include "lc_model.h"
 #include "piece.h"
 #include "group.h"
 
-lcQEditGroupsDialog::lcQEditGroupsDialog(QWidget* Parent, const QMap<lcPiece*, lcGroup*>& PieceParents, const QMap<lcGroup*, lcGroup*>& GroupParents, lcModel* Model)
-	: QDialog(Parent), mPieceParents(PieceParents), mGroupParents(GroupParents)
+constexpr uintptr_t LC_GROUPDIALOG_NEW_GROUP = ~0;
+
+class lcEditGroupsDialogDelegate : public QItemDelegate
+{
+public:
+	lcEditGroupsDialogDelegate(QObject* Parent)
+	    : QItemDelegate(Parent)
+	{
+	}
+	
+	void setModelData(QWidget* Editor, QAbstractItemModel* Model, const QModelIndex& Index) const
+	{
+		QLineEdit* LineEdit = qobject_cast<QLineEdit *>(Editor);
+		
+		if (!LineEdit->isModified())
+			return;
+
+		QString Text = LineEdit->text().trimmed();
+		
+		lcQEditGroupsDialog* Dialog = qobject_cast<lcQEditGroupsDialog*>(parent());
+		
+		if (Dialog && !Dialog->CanRenameGroup(Text))
+			return;
+		
+		QItemDelegate::setModelData(Editor, Model, Index);
+	}
+};
+
+lcQEditGroupsDialog::lcQEditGroupsDialog(QWidget* Parent, const lcModel* Model)
+    : QDialog(Parent), mModel(Model)
 {
-	mLastItemClicked = nullptr;
-	mModel = Model;
 	ui = new Ui::lcQEditGroupsDialog;
 
 	ui->setupUi(this);
+		
+	QPushButton* NewGroup = ui->buttonBox->addButton(tr("&New Group"), QDialogButtonBox::ActionRole);
 
-	connect(ui->treeWidget, &QTreeWidget::itemClicked, this, &lcQEditGroupsDialog::onItemClicked);
-	connect(ui->treeWidget, &QTreeWidget::itemDoubleClicked, this, &lcQEditGroupsDialog::onItemDoubleClicked);
+	connect(NewGroup, &QPushButton::clicked, this, &lcQEditGroupsDialog::NewGroupClicked);
 
-	QPushButton *newGroup = ui->buttonBox->addButton(tr("New Group"), QDialogButtonBox::ActionRole);
-
-	connect(newGroup, &QPushButton::clicked, this, &lcQEditGroupsDialog::on_newGroup_clicked);
-
-	AddChildren(ui->treeWidget->invisibleRootItem(), nullptr);
+	PopulateTree();
+	
+	ui->treeWidget->setItemDelegate(new lcEditGroupsDialogDelegate(this));
 	ui->treeWidget->expandAll();
 }
 
@@ -31,139 +55,164 @@ lcQEditGroupsDialog::~lcQEditGroupsDialog()
 	delete ui;
 }
 
-void lcQEditGroupsDialog::accept()
+bool lcQEditGroupsDialog::CanRenameGroup(const QString& Text) const
 {
-	UpdateParents(ui->treeWidget->invisibleRootItem(), nullptr);
-
-	QDialog::accept();
+	if (Text.isEmpty())
+		return false;
+	
+	std::function<bool(QTreeWidgetItem*)> ScanGroups = [&ScanGroups, &Text](QTreeWidgetItem* ParentItem)
+	{
+		for (int ChildIndex = 0; ChildIndex < ParentItem->childCount(); ChildIndex++)
+		{
+			QTreeWidgetItem* ChildItem = ParentItem->child(ChildIndex);
+			
+			if (ChildItem->data(0, GroupRole).value<uintptr_t>())
+			{
+				if (ChildItem->text(0) == Text || !ScanGroups(ChildItem))
+					return false;
+			}
+		}
+		
+		return true;
+	};
+	
+	return ScanGroups(ui->treeWidget->invisibleRootItem());
 }
 
-void lcQEditGroupsDialog::reject()
-{
-	for (int GroupIdx = 0; GroupIdx < mNewGroups.size(); GroupIdx++)
-		mModel->RemoveGroup(mNewGroups[GroupIdx]);
-
-	QDialog::reject();
-}
-
-void lcQEditGroupsDialog::on_newGroup_clicked()
+void lcQEditGroupsDialog::NewGroupClicked()
 {
 	QTreeWidgetItem* CurrentItem = ui->treeWidget->currentItem();
-
+	
 	if (CurrentItem && CurrentItem->data(0, PieceRole).value<uintptr_t>())
 		CurrentItem = CurrentItem->parent();
-
+	
 	if (!CurrentItem)
 		CurrentItem = ui->treeWidget->invisibleRootItem();
-
-	lcGroup* ParentGroup = (lcGroup*)CurrentItem->data(0, GroupRole).value<uintptr_t>();
-
-	lcGroup* NewGroup = mModel->AddGroup(tr("Group #"), ParentGroup);
-	mGroupParents[NewGroup] = ParentGroup;
-	mNewGroups.append(NewGroup);
-
-	QTreeWidgetItem* GroupItem = new QTreeWidgetItem(CurrentItem, QStringList(NewGroup->mName));
+	
+	QString Prefix = tr("Group #");
+	int MaxIndex = 0;
+	
+	std::function<void(QTreeWidgetItem*)> ScanGroups = [&ScanGroups, &Prefix, &MaxIndex](QTreeWidgetItem* ParentItem)
+	{
+		for (int ChildIndex = 0; ChildIndex < ParentItem->childCount(); ChildIndex++)
+		{
+			QTreeWidgetItem* ChildItem = ParentItem->child(ChildIndex);
+			
+			if (ChildItem->data(0, GroupRole).value<uintptr_t>())
+			{
+				QString Name = ChildItem->text(0);
+				
+				if (Name.startsWith(Prefix))
+				{
+					bool Ok = false;
+					int GroupNumber = Name.mid(Prefix.length()).toInt(&Ok);
+					
+					if (Ok && GroupNumber > MaxIndex)
+						MaxIndex = GroupNumber;
+				}
+				
+				ScanGroups(ChildItem);
+			}
+		}		
+	};
+	
+	ScanGroups(ui->treeWidget->invisibleRootItem());
+	
+	QString Name = Prefix + QString::number(MaxIndex + 1);
+	
+	QTreeWidgetItem* GroupItem = new QTreeWidgetItem(CurrentItem, QStringList(Name));
 	GroupItem->setFlags(Qt::ItemIsSelectable | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled | Qt::ItemIsEditable);
-	GroupItem->setData(0, GroupRole, QVariant::fromValue<uintptr_t>((uintptr_t)NewGroup));
+	GroupItem->setData(0, GroupRole, QVariant::fromValue<uintptr_t>(LC_GROUPDIALOG_NEW_GROUP));
+	GroupItem->setExpanded(true);
 }
 
-void lcQEditGroupsDialog::onItemClicked(QTreeWidgetItem *item, int column)
+lcQEditGroupsDialog::GroupInfo lcQEditGroupsDialog::GetGroupInfo(QTreeWidgetItem* ParentItem) const
 {
-	Q_UNUSED(column);
-
-	if (item->flags() & Qt::ItemIsEditable)
+	lcQEditGroupsDialog::GroupInfo GroupInfo;
+	
+	GroupInfo.Name = ParentItem->text(0);
+	
+	uintptr_t GroupPointer = ParentItem->data(0, GroupRole).value<uintptr_t>();
+	GroupInfo.Group = (GroupPointer == LC_GROUPDIALOG_NEW_GROUP) ? nullptr : reinterpret_cast<lcGroup*>(GroupPointer);
+	
+	for (int ChildIndex = 0; ChildIndex < ParentItem->childCount(); ChildIndex++)
 	{
-		mClickTimer.stop();
-
-		if (mLastItemClicked != item)
-		{
-			mLastItemClicked = item;
-			mEditableDoubleClicked = false;
-		}
+		QTreeWidgetItem* ChildItem = ParentItem->child(ChildIndex);
+		
+		if (ChildItem->data(0, GroupRole).value<uintptr_t>())
+			GroupInfo.ChildGroups.emplace_back(GetGroupInfo(ChildItem));
 		else
 		{
-			mClickTimer.start(QApplication::doubleClickInterval() + 50, this);
+			lcPiece* Piece = reinterpret_cast<lcPiece*>(ChildItem->data(0, PieceRole).value<uintptr_t>());
+			
+			if (Piece)
+				GroupInfo.ChildPieces.push_back(Piece);
 		}
-	}
+	}	
+	
+	return GroupInfo;
 }
 
-void lcQEditGroupsDialog::onItemDoubleClicked(QTreeWidgetItem *item, int column)
+lcQEditGroupsDialog::GroupInfo lcQEditGroupsDialog::GetGroups() const
 {
-	Q_UNUSED(column);
-
-	if (item->flags() & Qt::ItemIsEditable)
-	{
-		mEditableDoubleClicked = true;
-	}
+	return GetGroupInfo(ui->treeWidget->invisibleRootItem());
 }
 
-void lcQEditGroupsDialog::timerEvent(QTimerEvent *event)
+void lcQEditGroupsDialog::PopulateTree()
 {
-	Q_UNUSED(event);
-
-	mClickTimer.stop();
-	if (!mEditableDoubleClicked)
+	const std::vector<std::unique_ptr<lcGroup>>& Groups = mModel->GetGroups();
+	std::unordered_map<lcGroup*, QTreeWidgetItem*> AddedGroups;
+	std::vector<lcGroup*> GroupsToAdd;
+	
+	AddedGroups[nullptr] = ui->treeWidget->invisibleRootItem();
+	
+	auto CreateGroupItem = [&AddedGroups](lcGroup* Group)
 	{
-		ui->treeWidget->editItem(mLastItemClicked);
-	}
-
-	mEditableDoubleClicked = false;
-}
-
-void lcQEditGroupsDialog::UpdateParents(QTreeWidgetItem* ParentItem, lcGroup* ParentGroup)
-{
-	for (int ChildIdx = 0; ChildIdx < ParentItem->childCount(); ChildIdx++)
-	{
-		QTreeWidgetItem* ChildItem = ParentItem->child(ChildIdx);
-
-		lcPiece* Piece = (lcPiece*)ChildItem->data(0, PieceRole).value<uintptr_t>();
-
-		if (Piece)
-		{
-			mPieceParents[Piece] = ParentGroup;
-		}
-		else
-		{
-			lcGroup* Group = (lcGroup*)ChildItem->data(0, GroupRole).value<uintptr_t>();
-
-			// todo: validate unique group name
-			if (Group)
-				Group->mName = ChildItem->text(0);
-
-			mGroupParents[Group] = ParentGroup;
-
-			UpdateParents(ChildItem, Group);
-		}
-	}
-}
-
-void lcQEditGroupsDialog::AddChildren(QTreeWidgetItem* ParentItem, lcGroup* ParentGroup)
-{
-	for (QMap<lcGroup*, lcGroup*>::const_iterator it = mGroupParents.constBegin(); it != mGroupParents.constEnd(); it++)
-	{
-		lcGroup* Group = it.key();
-		lcGroup* Parent = it.value();
-
-		if (Parent != ParentGroup)
-			continue;
-
+		QTreeWidgetItem* ParentItem = AddedGroups.find(Group->mGroup)->second;
+		
+		if (!ParentItem)
+			return false;
+		
 		QTreeWidgetItem* GroupItem = new QTreeWidgetItem(ParentItem, QStringList(Group->mName));
 		GroupItem->setFlags(Qt::ItemIsSelectable | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled | Qt::ItemIsEditable);
 		GroupItem->setData(0, GroupRole, QVariant::fromValue<uintptr_t>((uintptr_t)Group));
-
-		AddChildren(GroupItem, Group);
-	}
-
-	for (QMap<lcPiece*, lcGroup*>::const_iterator it = mPieceParents.constBegin(); it != mPieceParents.constEnd(); it++)
+		
+		AddedGroups[Group] = GroupItem;
+		
+		return true;
+	};
+	
+	for (const std::unique_ptr<lcGroup>& Group : Groups)
+		if (!CreateGroupItem(Group.get()))
+			GroupsToAdd.push_back(Group.get());
+	
+	while (!GroupsToAdd.empty())
 	{
-		lcPiece* Piece = it.key();
-		lcGroup* Parent = it.value();
-
-		if (Parent != ParentGroup)
-			continue;
-
-		QTreeWidgetItem* PieceItem = new QTreeWidgetItem(ParentItem, QStringList(Piece->GetName()));
-		PieceItem->setFlags(Qt::ItemIsSelectable | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsDragEnabled);
-		PieceItem->setData(0, PieceRole, QVariant::fromValue<uintptr_t>((uintptr_t)Piece));
+		size_t GroupCount = GroupsToAdd.size();
+		
+		for (auto GroupIt = GroupsToAdd.begin(); GroupIt != GroupsToAdd.end();)
+		{
+			if (CreateGroupItem(*GroupIt))
+				GroupIt = GroupsToAdd.erase(GroupIt);
+			else
+				++GroupIt;
+		}
+		
+		if (GroupCount == GroupsToAdd.size())
+			break;
+	}
+	
+	const std::vector<std::unique_ptr<lcPiece>>& Pieces = mModel->GetPieces();
+	
+	for (const std::unique_ptr<lcPiece>& Piece : Pieces)
+	{
+		QTreeWidgetItem* ParentItem = AddedGroups.find(Piece->GetGroup())->second;
+		
+		if (ParentItem)
+		{
+			QTreeWidgetItem* PieceItem = new QTreeWidgetItem(ParentItem, QStringList(Piece->GetName()));
+			PieceItem->setFlags(Qt::ItemIsSelectable | Qt::ItemIsUserCheckable | Qt::ItemIsEnabled | Qt::ItemIsDragEnabled);
+			PieceItem->setData(0, PieceRole, QVariant::fromValue<uintptr_t>((uintptr_t)Piece.get()));
+		}
 	}
 }
diff --git a/qt/lc_qeditgroupsdialog.h b/qt/lc_qeditgroupsdialog.h
index b05dca2c..b4f7286a 100644
--- a/qt/lc_qeditgroupsdialog.h
+++ b/qt/lc_qeditgroupsdialog.h
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <QDialog>
-
 namespace Ui {
 class lcQEditGroupsDialog;
 }
@@ -11,37 +9,33 @@ class lcQEditGroupsDialog : public QDialog
 	Q_OBJECT
 	
 public:
-	lcQEditGroupsDialog(QWidget* Parent, const QMap<lcPiece*, lcGroup*>& PieceParents, const QMap<lcGroup*, lcGroup*>& GroupParents, lcModel* Model);
-	~lcQEditGroupsDialog();
+	lcQEditGroupsDialog(QWidget* Parent, const lcModel* Model);
+	virtual ~lcQEditGroupsDialog();
 	
-	QMap<lcPiece*, lcGroup*> mPieceParents;
-	QMap<lcGroup*, lcGroup*> mGroupParents;
-	QList<lcGroup*> mNewGroups;
-	//QList<lcGroup*> mDeletedGroups; // todo: support deleting groups in the edit groups dialog
+	struct GroupInfo
+	{
+		QString Name;
+		lcGroup* Group;
+		std::vector<GroupInfo> ChildGroups;
+		std::vector<lcPiece*> ChildPieces;
+	};
+	
+	GroupInfo GetGroups() const;
+	bool CanRenameGroup(const QString& Text) const;
+	
+protected slots:
+	void NewGroupClicked();
 
+protected:
 	enum
 	{
 		PieceRole = Qt::UserRole,
 		GroupRole
 	};
-
-public slots:
-	void accept() override;
-	void reject() override;
-	void on_newGroup_clicked();
-	void onItemClicked(QTreeWidgetItem* Item, int Column);
-	void onItemDoubleClicked(QTreeWidgetItem* Item, int Column);
-
-private:
-	Ui::lcQEditGroupsDialog *ui;
-
-	void UpdateParents(QTreeWidgetItem* ParentItem, lcGroup* ParentGroup);
-	void AddChildren(QTreeWidgetItem* ParentItem, lcGroup* ParentGroup);
-
-	void timerEvent(QTimerEvent* Event) override;
-
-	lcModel* mModel;
-	QTreeWidgetItem* mLastItemClicked;
-	bool mEditableDoubleClicked;
-	QBasicTimer mClickTimer;
+	
+	GroupInfo GetGroupInfo(QTreeWidgetItem* ParentItem) const;
+	void PopulateTree();
+	
+	Ui::lcQEditGroupsDialog* ui = nullptr;
+	const lcModel* mModel = nullptr;
 };
diff --git a/qt/lc_qeditgroupsdialog.ui b/qt/lc_qeditgroupsdialog.ui
index 522be73a..d2b58f15 100644
--- a/qt/lc_qeditgroupsdialog.ui
+++ b/qt/lc_qeditgroupsdialog.ui
@@ -17,13 +17,13 @@
    <item>
     <widget class="QTreeWidget" name="treeWidget">
      <property name="editTriggers">
-      <set>QAbstractItemView::NoEditTriggers</set>
+      <set>QAbstractItemView::EditTrigger::DoubleClicked|QAbstractItemView::EditTrigger::EditKeyPressed|QAbstractItemView::EditTrigger::SelectedClicked</set>
      </property>
      <property name="dragEnabled">
       <bool>true</bool>
      </property>
      <property name="dragDropMode">
-      <enum>QAbstractItemView::InternalMove</enum>
+      <enum>QAbstractItemView::DragDropMode::InternalMove</enum>
      </property>
      <property name="uniformRowHeights">
       <bool>true</bool>
@@ -41,10 +41,10 @@
    <item>
     <widget class="QDialogButtonBox" name="buttonBox">
      <property name="orientation">
-      <enum>Qt::Horizontal</enum>
+      <enum>Qt::Orientation::Horizontal</enum>
      </property>
      <property name="standardButtons">
-      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+      <set>QDialogButtonBox::StandardButton::Cancel|QDialogButtonBox::StandardButton::Ok</set>
      </property>
     </widget>
    </item>