diff --git a/include/nana/gui/widgets/group.hpp b/include/nana/gui/widgets/group.hpp
index 1985c961..6ec70c0a 100644
--- a/include/nana/gui/widgets/group.hpp
+++ b/include/nana/gui/widgets/group.hpp
@@ -67,6 +67,10 @@ namespace nana{
 		group& collocate() noexcept;
 		group& div(const char* div_str) noexcept;
 		field_reference operator[](const char* field);
+
+		void field_display(const char* field_name, bool display); ///<Displays/Discards an existing field.
+		bool field_display(const char* field_name) const;	///<Determines whether the specified field is displayed.
+		void erase(window handle);				///< Erases a window from field.
 		
 		template<typename Widget, typename ...Args>
 		Widget* create_child(const char* field, Args && ... args)
diff --git a/include/nana/gui/widgets/listbox.hpp b/include/nana/gui/widgets/listbox.hpp
index aecf1ade..0202d028 100644
--- a/include/nana/gui/widgets/listbox.hpp
+++ b/include/nana/gui/widgets/listbox.hpp
@@ -1429,6 +1429,8 @@ the nana::detail::basic_window member pointer scheme
 		size_type append_header(std::string text_utf8, unsigned width = 120);
 		size_type append_header(std::wstring text, unsigned width = 120);
 
+		void clear_headers();					///< Removes all the columns.
+
 		cat_proxy append(std::string category);		///< Appends a new category to the end
 		cat_proxy append(std::wstring category);		///< Appends a new category to the end
 		void append(std::initializer_list<std::string> categories); ///< Appends categories to the end
diff --git a/include/nana/gui/widgets/menubar.hpp b/include/nana/gui/widgets/menubar.hpp
index 24c965b5..75158284 100644
--- a/include/nana/gui/widgets/menubar.hpp
+++ b/include/nana/gui/widgets/menubar.hpp
@@ -95,6 +95,7 @@ namespace nana
 		menu& push_back(const std::string&);	///< Appends a new (empty) menu.
 		menu& at(size_t index) const;		    ///< Gets the menu specified by index.
 		std::size_t length() const;		        ///< Number of menus.
+		void clear();							///< Removes all the menus.
 		
 		/// Deselects the menu
 		/**
diff --git a/include/nana/gui/widgets/toolbar.hpp b/include/nana/gui/widgets/toolbar.hpp
index cc0f4e24..02e88c6c 100644
--- a/include/nana/gui/widgets/toolbar.hpp
+++ b/include/nana/gui/widgets/toolbar.hpp
@@ -1,7 +1,7 @@
 /**
  *	A Toolbar Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2016 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2018 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -98,6 +98,8 @@ namespace nana
 		void separate();                      ///< Adds a separator.
 		drawerbase::toolbar::item_proxy append(const ::std::string& text, const nana::paint::image& img);   ///< Adds a control button.
 		drawerbase::toolbar::item_proxy append(const ::std::string& text);   ///< Adds a control button.
+		void clear();   ///< Removes all control buttons and separators.
+		
 		bool enable(size_type index) const;
 		void enable(size_type index, bool enable_state);
 		void scale(unsigned s);   ///< Sets the scale of control button.
diff --git a/source/gui/place.cpp b/source/gui/place.cpp
index 7c66b0aa..d4ecf449 100644
--- a/source/gui/place.cpp
+++ b/source/gui/place.cpp
@@ -3271,6 +3271,22 @@ namespace nana
 
 			modified_ptr->div_owner = div_owner;
 			modified_ptr->div_next = div_next;
+
+			if (div_owner)
+			{
+				implement::division * pv_div = nullptr;
+				//Updates the div_next of the div at front of modified one.
+				for (auto & div : div_owner->children)
+				{
+					if (div.get() == modified_ptr)
+					{
+						if (pv_div)
+							pv_div->div_next = modified_ptr;
+						break;
+					}
+					pv_div = div.get();
+				}
+			}
 		}
 		catch (...)
 		{
diff --git a/source/gui/widgets/group.cpp b/source/gui/widgets/group.cpp
index f84058ea..b3c2658d 100644
--- a/source/gui/widgets/group.cpp
+++ b/source/gui/widgets/group.cpp
@@ -194,6 +194,21 @@ namespace nana{
 		return impl_->place_content.field(field);
 	}
 
+	void group::field_display(const char* field_name, bool display)
+	{
+		impl_->place_content.field_display(field_name, display);
+	}
+
+	bool group::field_display(const char* field_name) const
+	{
+		return impl_->place_content.field_display(field_name);
+	}
+
+	void group::erase(window handle)
+	{
+		impl_->place_content.erase(handle);
+	}
+
 	void group::_m_add_child(const char* field, widget* wdg)
 	{
 		impl_->place_content[field] << wdg->handle();
diff --git a/source/gui/widgets/listbox.cpp b/source/gui/widgets/listbox.cpp
index 3253a882..d26143ea 100644
--- a/source/gui/widgets/listbox.cpp
+++ b/source/gui/widgets/listbox.cpp
@@ -316,6 +316,11 @@ namespace nana
                     return cont_.back().index;
 				}
 
+				void clear()
+				{
+					cont_.clear();
+				}
+
 				unsigned width_px() const noexcept  ///< the visible width of the whole header
 				{
 					unsigned pixels = 0;
@@ -1538,9 +1543,37 @@ namespace nana
 					return n;
 				}
 
-				template<typename Pred>
-				std::vector<std::pair<index_pair, bool>> select_display_range_if(const index_pair& fr_abs, index_pair to_dpl, bool deselect_others, Pred pred)
+				/// Finds a good item or category if an item specified by pos is invaild
+				index_pair find_next_good(index_pair pos, bool ignore_category) const noexcept
 				{
+					//Return the pos if it is good
+					if (this->good(pos))
+						return pos;
+					
+					while(pos.cat < this->categories_.size())
+					{
+						if ((pos.npos == pos.item) && !ignore_category)
+							return pos;
+
+						auto cat_item_size = this->get(pos.cat)->items.size();
+
+						if (pos.item < cat_item_size)
+							return pos;
+
+						if ((pos.npos == pos.item) && (cat_item_size > 0) && ignore_category)
+							return index_pair{ pos.cat, 0 };
+
+						++pos.cat;
+						pos.item = pos.npos;
+					}
+					return index_pair{};
+				}
+
+				template<typename Pred>
+				std::vector<std::pair<index_pair, bool>> select_display_range_if(index_pair fr_abs, index_pair to_dpl, bool deselect_others, Pred pred)
+				{
+					fr_abs = find_next_good(fr_abs, true);
+					
 					if (to_dpl.empty())
 					{
 						if (fr_abs.empty())
@@ -1548,6 +1581,7 @@ namespace nana
 
 						to_dpl = this->last();
 					}
+					
 
 					auto fr_dpl = (fr_abs.is_category() ? fr_abs : this->index_cast(fr_abs, false));	//Converts an absolute position to display position
                     if (fr_dpl > to_dpl)
@@ -5467,6 +5501,15 @@ namespace nana
 			return pos;
 		}
 
+		void listbox::clear_headers()
+		{
+			internal_scope_guard lock;
+			auto & ess = _m_ess();
+			ess.lister.erase();
+			ess.header.clear();
+			ess.update();
+		}
+
 		listbox::cat_proxy listbox::append(std::string s)
 		{
 			internal_scope_guard lock;
diff --git a/source/gui/widgets/menubar.cpp b/source/gui/widgets/menubar.cpp
index 5071c094..3c211ba6 100644
--- a/source/gui/widgets/menubar.cpp
+++ b/source/gui/widgets/menubar.cpp
@@ -625,6 +625,13 @@ namespace nana
 		{
 			return get_drawer_trigger().ess().items.size();
 		}
+		
+		void menubar::clear()
+		{
+			internal_scope_guard lock;
+			get_drawer_trigger().ess().items.clear();
+			API::refresh_window(handle());
+		}
 
 		bool menubar::cancel()
 		{
diff --git a/source/gui/widgets/toolbar.cpp b/source/gui/widgets/toolbar.cpp
index d34fc524..963b99cf 100644
--- a/source/gui/widgets/toolbar.cpp
+++ b/source/gui/widgets/toolbar.cpp
@@ -1,7 +1,7 @@
 /*
  *	A Toolbar Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2018 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -55,8 +55,7 @@ namespace nana
 
 				~item_container()
 				{
-					for(auto ptr : cont_)
-						delete ptr;
+					clear();
 				}
 
 				void insert(size_type pos, std::string text, const nana::paint::image& img, item_type::kind type)
@@ -118,6 +117,15 @@ namespace nana
 				{
 					return cont_.at(pos);
 				}
+
+				void clear()
+				{
+					for(auto ptr : cont_)
+						delete ptr;
+
+					cont_.clear();
+				}
+
 			private:
 				container_type cont_;
 				size_t    right_{ npos };
@@ -467,6 +475,12 @@ namespace nana
 			return {*this, get_drawer_trigger().items().size() - 1u};
 		}
 
+		void toolbar::clear()
+		{
+			get_drawer_trigger().items().clear();
+			API::refresh_window(this->handle());
+		}
+
 		bool toolbar::enable(size_type pos) const
 		{
 			auto & items = get_drawer_trigger().items();
diff --git a/source/gui/widgets/treebox.cpp b/source/gui/widgets/treebox.cpp
index 88468861..ac4c2799 100644
--- a/source/gui/widgets/treebox.cpp
+++ b/source/gui/widgets/treebox.cpp
@@ -1,7 +1,7 @@
 /*
  *	A Treebox Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2018 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
@@ -958,10 +958,14 @@ namespace nana
 					return *this;
 				}
 
+
 				std::size_t item_proxy::size() const
 				{
 					std::size_t n = 0;
-					for(auto child = node_->child; child; child = child->child)
+
+					//Fixed by ErrorFlynn
+					//this method incorrectly returned the number of levels beneath the nodes using child = child->child
+					for(auto child = node_->child; child; child = child->next)
 						++n;
 
 					return n;