Fix merge

# Conflicts:
#	include/nana/gui/widgets/treebox.hpp
#	source/gui/place.cpp

.travis.yml

@@ -46,8 +46,6 @@ before_install:
   - cd ..
   - git clone --depth=1 --branch=hotfix https://github.com/qPCR4vir/nana-demo.git nana-demo
   - export PATH="$HOME/bin:$PATH"
-
-  #- mkdir ~/bin #it seemd that a bin already exists from 20170901 
   - wget --no-check-certificate --no-clobber -O /tmp/tools/cmake https://cmake.org/files/v3.12/cmake-3.12.0-rc3-Linux-x86_64.sh || true
   - chmod -R +x /tmp/tools
 

build/vc2017/nana.vcxproj

@@ -256,6 +256,7 @@
     <ClInclude Include="..\..\include\nana\gui.hpp" />
     <ClInclude Include="..\..\include\nana\gui\animation.hpp" />
     <ClInclude Include="..\..\include\nana\gui\basis.hpp" />
+    <ClInclude Include="..\..\include\nana\gui\dragdrop.hpp" />
     <ClInclude Include="..\..\include\nana\gui\dragger.hpp" />
     <ClInclude Include="..\..\include\nana\gui\drawing.hpp" />
     <ClInclude Include="..\..\include\nana\gui\effects.hpp" />

build/vc2017/nana.vcxproj.filters

@@ -474,6 +474,9 @@
     <ClInclude Include="..\..\include\nana\verbose_preprocessor.hpp">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\include\nana\gui\dragdrop.hpp">
+      <Filter>Include\gui</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\..\include\nana\pop_ignore_diagnostic">

include/nana/gui/dragdrop.hpp

@@ -40,7 +40,16 @@ namespace nana
 		simple_dragdrop(simple_dragdrop&&) = delete;
 		simple_dragdrop& operator=(simple_dragdrop&&) = delete;
 	public:
-		simple_dragdrop(window source);
+		explicit simple_dragdrop(window source);
+		simple_dragdrop(window                drag_origin,
+						std::function<bool()> when,
+						window                drop_target,
+						std::function<void()> how)
+		: simple_dragdrop{drag_origin}
+		{
+			condition(when);
+			make_drop(drop_target, how);
+		}
 		~simple_dragdrop();
 
 		/// Condition checker

include/nana/gui/widgets/group.hpp

@@ -59,7 +59,6 @@ namespace nana{
 		group(window parent, const rectangle& = {}, bool visible = true);
 
 		///  The construction that creates the widget and set the title or caption
-
 		group(window			parent,		        ///< a handle to the parent
 			  ::std::string	    title,		        ///< caption of the group
 			  bool				formatted = false,  ///< Enable/disable the formatted text for the title

include/nana/gui/widgets/treebox.hpp

@@ -350,9 +350,9 @@ namespace nana
     /// \brief  Displays a hierarchical list of items, such as the files and directories on a disk.
     /// See also in [documentation](http://nanapro.org/en-us/documentation/widgets/treebox.htm)
     class treebox
-		:public widget_object < category::widget_tag,
+		:public widget_object <category::widget_tag,
 		                        drawerbase::treebox::trigger,
-		                        drawerbase::treebox::treebox_events>
+		                        drawerbase::treebox::treebox_events, drawerbase::treebox::scheme>
 	{
 	public:
         /// A type refers to the item and is also used to iterate through the nodes.