fix caret issue

include/nana/gui/basis.hpp

@@ -273,6 +273,7 @@ that return a corresponding nana::appearance with predefined values.
 	public:
 		virtual ~caret_interface() = default;
 
+		virtual bool activated() const = 0;
 		virtual void disable_throw() noexcept = 0;
 
 		virtual void effective_range(const rectangle& range) = 0;

include/nana/gui/detail/basic_window.hpp

@@ -55,6 +55,7 @@ namespace detail
 		void dimension(const size& s) override;
 		void visible(bool visibility) override;
 		bool visible() const override;
+		bool activated() const override;
 	private:
 		basic_window * owner_;
 		point	position_;

source/gui/detail/basic_window.cpp

@@ -204,6 +204,11 @@ namespace nana
 			{
 				return (visible_state::invisible != visibility_);
 			}
+
+			bool caret::activated() const
+			{
+				return (visible_state::displayed == visibility_);
+			}
 		//end class caret
 
 		//struct basic_window
@@ -329,24 +334,18 @@ namespace nana
 				return false;
 			}
 
-			const basic_window* get_child_caret(const basic_window* wd, bool this_is_a_child)
-			{
-				if (this_is_a_child && wd->annex.caret_ptr)
-					return wd;
-
-				for (auto child : wd->children)
-				{
-					auto caret_wd = get_child_caret(child, true);
-					if (caret_wd)
-						return caret_wd;
-				}
-
-				return nullptr;
-			}
-
 			const basic_window * basic_window::child_caret() const
 			{
-				return get_child_caret(this, false);
+				for (auto child : children) {
+					//Only return the child who has activated caret.
+					if (child->annex.caret_ptr && child->annex.caret_ptr->activated())
+						return child;
+
+					auto caret = child->child_caret();
+					if (caret)
+						return caret;
+				}
+				return nullptr;
 			}
 
 			bool basic_window::is_draw_through() const

source/gui/detail/bedrock_pi.cpp

@@ -151,7 +151,8 @@ namespace nana
 			arg.window_handle = reinterpret_cast<window>(wd);
 			if (emit(event_code::expose, wd, arg, false, get_thread_context()))
 			{
-				const core_window_t * caret_wd = (wd->annex.caret_ptr ? wd : wd->child_caret());
+				//Get the window who has the activated caret
+				const core_window_t * caret_wd = ((wd->annex.caret_ptr && wd->annex.caret_ptr->activated()) ? wd : wd->child_caret());
 				if (caret_wd)
 				{
 					if (exposed)

source/gui/programming_interface.cpp

@@ -1183,6 +1183,13 @@ namespace API
 			auto caret = _m_caret();
 			return (caret && caret->visible());
 		}
+
+		bool activated() const override
+		{
+			internal_scope_guard lock;
+			auto caret = _m_caret();
+			return (caret && caret->activated());
+		}
 	private:
 		caret_interface* _m_caret() const
 		{