fix a caret issue which happens when parent widget is hidden

include/nana/gui/detail/basic_window.hpp

@@ -118,9 +118,11 @@ namespace detail
 
 		bool is_ancestor_of(const basic_window* wd) const;
 		bool visible_parents() const;
+		bool displayed() const;
 		bool belong_to_lazy() const;
+		const basic_window * child_caret() const; //Returns a child which owns a caret
 
-		bool is_draw_through() const;	///< Determines whether it is a draw-through window.
+		bool is_draw_through() const;	// Determines whether it is a draw-through window.
 	public:
 		//Override event_holder
 		bool set_events(const std::shared_ptr<general_events>&) override;

source/gui/detail/basic_window.cpp

@@ -282,6 +282,11 @@ namespace nana
 				return true;
 			}
 
+			bool basic_window::displayed() const
+			{
+				return (visible && visible_parents());
+			}
+
 			bool basic_window::belong_to_lazy() const
 			{
 				for (auto wd = this; wd; wd = wd->parent)
@@ -292,6 +297,26 @@ 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->together.caret)
+					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);
+			}
+
 			bool basic_window::is_draw_through() const
 			{
 				if (::nana::category::flags::root == this->other.category)

source/gui/detail/bedrock_pi.cpp

@@ -63,15 +63,16 @@ namespace nana
 			arg.window_handle = reinterpret_cast<window>(wd);
 			if (emit(event_code::expose, wd, arg, false, get_thread_context()))
 			{
-				if (wd->together.caret)
+				const core_window_t * caret_wd = (wd->together.caret ? wd : wd->child_caret());
+				if (caret_wd)
 				{
 					if (exposed)
 					{
-						if (wd->root_widget->other.attribute.root->focus == wd)
+						if (wd->root_widget->other.attribute.root->focus == caret_wd)
-							wd->together.caret->visible(true);
+							caret_wd->together.caret->visible(true);
 					}
 					else
-						wd->together.caret->visible(false);
+						caret_wd->together.caret->visible(false);
 				}
 
 				if (!exposed)

source/gui/detail/win32/bedrock.cpp

@@ -363,7 +363,7 @@ namespace detail
 	void bedrock::pump_event(window modal_window, bool is_modal)
 	{
 		const unsigned tid = ::GetCurrentThreadId();
-		thread_context * context = this->open_thread_context(tid);
+		auto context = this->open_thread_context(tid);
 		if(0 == context->window_count)
 		{
 			//test if there is not a window

source/gui/detail/window_layout.cpp

@@ -354,7 +354,7 @@ namespace nana
 				nana::rectangle r_of_sigwd(sigwd->pos_root, sigwd->dimension);
 				for (auto wd : data_sect.effects_bground_windows)
 				{
-					if (wd == sigwd || !wd->visible || !wd->visible_parents() ||
+					if (wd == sigwd || !wd->displayed() ||
 						(false == overlap(nana::rectangle{ wd->pos_root, wd->dimension }, r_of_sigwd)))
 						continue;
 

source/gui/detail/window_manager.cpp

@@ -698,7 +698,7 @@ namespace detail
 			std::lock_guard<decltype(mutex_)> lock(mutex_);
 			if (impl_->wd_register.available(wd) == false) return false;
 
-			if (wd->visible && wd->visible_parents())
+			if (wd->displayed())
 			{
 				if(forced || (false == wd->belong_to_lazy()))
 				{
@@ -722,7 +722,7 @@ namespace detail
 			std::lock_guard<decltype(mutex_)> lock(mutex_);
 
 			//It's not worthy to redraw if visible is false
-			if (impl_->wd_register.available(wd) && wd->visible && wd->visible_parents())
+			if (impl_->wd_register.available(wd) && wd->displayed())
 				window_layer::paint(wd, true, true);
 		}
 
@@ -1060,7 +1060,7 @@ namespace detail
 			bool precondition = false;
 			for (auto & tab_wd : tabs)
 			{
-				if (tab_wd->visible)
+				if (tab_wd->displayed())
 				{
 					precondition = true;
 					break;