diff --git a/source/gui/widgets/checkbox.cpp b/source/gui/widgets/checkbox.cpp
index 3148ee88..fc08fcac 100644
--- a/source/gui/widgets/checkbox.cpp
+++ b/source/gui/widgets/checkbox.cpp
@@ -1,7 +1,7 @@
 /*
  *	A CheckBox Implementation
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2018 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2019 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
diff --git a/source/gui/widgets/listbox.cpp b/source/gui/widgets/listbox.cpp
index 895b2829..13baf15a 100644
--- a/source/gui/widgets/listbox.cpp
+++ b/source/gui/widgets/listbox.cpp
@@ -6197,8 +6197,8 @@ namespace nana
 			for(size_type i=first_col; i<=last_col; ++i) new_idx.push_back(i);
 			
 			internal_scope_guard lock;
-			const item_proxy ip_row = this->at(row);
-			const nana::any *pnany=_m_ess().lister.anyobj(row,false);
+			auto ip_row = this->at(row);
+			auto pnany=_m_ess().lister.anyobj(row,false);
 			std::sort(new_idx.begin(), new_idx.end(), [&](size_type col1,
 														  size_type col2)
 			{
diff --git a/source/gui/widgets/spinbox.cpp b/source/gui/widgets/spinbox.cpp
index 49ae0347..4a631c2c 100644
--- a/source/gui/widgets/spinbox.cpp
+++ b/source/gui/widgets/spinbox.cpp
@@ -1,7 +1,7 @@
 /*
  *	A Spin box widget
  *	Nana C++ Library(http://www.nanapro.org)
- *	Copyright(C) 2003-2017 Jinhao(cnjinhao@hotmail.com)
+ *	Copyright(C) 2003-2019 Jinhao(cnjinhao@hotmail.com)
  *
  *	Distributed under the Boost Software License, Version 1.0.
  *	(See accompanying file LICENSE_1_0.txt or copy at
diff --git a/source/gui/widgets/treebox.cpp b/source/gui/widgets/treebox.cpp
index 4181177e..e5be4dcd 100644
--- a/source/gui/widgets/treebox.cpp
+++ b/source/gui/widgets/treebox.cpp
@@ -1966,6 +1966,8 @@ namespace nana
 
 				void trigger::detached()
 				{
+					//Reset the comp_placer, because after deteching, the scheme refered by comp_placer will be released
+					impl_->data.comp_placer.reset();
 					impl_->data.graph = nullptr;
 				}