improve dockable place

add a new API::at_safe_place()

include/nana/gui/detail/window_manager.hpp

@@ -161,6 +161,9 @@ namespace detail
 		std::vector<std::pair<core_window_t*, unsigned long>> shortkeys(core_window_t*, bool with_children);
 
 		core_window_t* find_shortkey(native_window_type, unsigned long key);
+
+		void set_safe_place(core_window_t* wd, std::function<void()>&& fn);
+		void call_safe_place(unsigned thread_id);
 	private:
 		void _m_disengage(core_window_t*, core_window_t* for_new);
 		void _m_destroy(core_window_t*);

include/nana/gui/programming_interface.hpp

@@ -298,6 +298,8 @@ namespace API
 
 	bool ignore_mouse_focus(window, bool ignore);	///< Enables/disables the mouse focus, it returns the previous state
 	bool ignore_mouse_focus(window);				///< Determines whether the mouse focus is enabled
+
+	void at_safe_place(window, std::function<void()>);
 }//end namespace API
 }//end namespace nana
 

include/nana/gui/widgets/tabbar.hpp

@@ -379,6 +379,9 @@ namespace nana
 
 			void push_back(std::string text, ::nana::any par = {});
 			void push_front(std::string text, ::nana::any par = {});
+
+			std::size_t selected() const;
+			void erase(std::size_t pos, bool close_attached = true);
 		};
 }