diff --git a/source/gui/widgets/button.cpp b/source/gui/widgets/button.cpp
index a12a9415..241d3a63 100644
--- a/source/gui/widgets/button.cpp
+++ b/source/gui/widgets/button.cpp
@@ -235,7 +235,7 @@ namespace nana{	namespace drawerbase
 
 					if(shortkey)
 					{
-						unsigned off_w = (shortkey_pos ? graph.text_extent_size(mbstr.c_str(), static_cast<unsigned>(shortkey_pos)).width : 0);
+						unsigned off_w = (shortkey_pos ? graph.text_extent_size(mbstr.c_str(), shortkey_pos).width : 0);
 
 						wchar_t keystr[2] = {nana::utf::char_at(mbstr.c_str() + shortkey_pos, 0, 0), 0};
 						auto shortkey_size = graph.text_extent_size(keystr, 1);
diff --git a/source/gui/widgets/date_chooser.cpp b/source/gui/widgets/date_chooser.cpp
index 0085f30b..aa824637 100644
--- a/source/gui/widgets/date_chooser.cpp
+++ b/source/gui/widgets/date_chooser.cpp
@@ -393,7 +393,7 @@ namespace nana
 					int n = trace_.logic_pos.y * rows + trace_.logic_pos.x + 1;
 					if (page_mode::date == page)
 					{
-						if (n < 8) return false; //Here is week title bar
+						if (n < 8) return 0; //Here is week title bar
 						int dw = nana::date::day_of_week(view_month_.year, view_month_.month, 1);
 						n -= (dw ? dw + 7 : 14);
 					}
diff --git a/source/gui/widgets/float_listbox.cpp b/source/gui/widgets/float_listbox.cpp
index 8ad3c144..2b2d9180 100644
--- a/source/gui/widgets/float_listbox.cpp
+++ b/source/gui/widgets/float_listbox.cpp
@@ -155,7 +155,7 @@ namespace nana
 									--(state_.index);
 								else if(recycle)
 								{
-									state_.index = static_cast<unsigned>(module_->items.size() - 1);
+									state_.index = module_->items.size() - 1;
 									state_.offset_y = last_offset_y;
 								}
 
@@ -173,7 +173,7 @@ namespace nana
 								}
 
 								if(state_.index >= state_.offset_y + module_->max_items)
-									state_.offset_y = static_cast<unsigned>(state_.index - module_->max_items + 1);
+									state_.offset_y = state_.index - module_->max_items + 1;
 							}
 						}
 						else
diff --git a/source/gui/widgets/menubar.cpp b/source/gui/widgets/menubar.cpp
index e810d053..3d39b1f9 100644
--- a/source/gui/widgets/menubar.cpp
+++ b/source/gui/widgets/menubar.cpp
@@ -212,7 +212,7 @@ namespace nana
 
 						if (hotkey)
 						{
-							unsigned off_w = (hotkey_pos ? graph.text_extent_size(text.c_str(), static_cast<unsigned>(hotkey_pos)).width : 0);
+							unsigned off_w = (hotkey_pos ? graph.text_extent_size(text.c_str(), hotkey_pos).width : 0);
 							nana::size hotkey_size = graph.text_extent_size(text.c_str() + hotkey_pos, 1);
 
 							unsigned ascent, descent, inleading;
diff --git a/source/gui/widgets/tabbar.cpp b/source/gui/widgets/tabbar.cpp
index 61150e9f..b8824f3b 100644
--- a/source/gui/widgets/tabbar.cpp
+++ b/source/gui/widgets/tabbar.cpp
@@ -751,7 +751,7 @@ namespace nana
 					if((pos == npos) || (pos >= list_.size()))
 					{
 						this->list_.emplace_back();
-						pos = static_cast<unsigned>(list_.size() - 1);
+						pos = list_.size() - 1;
 					}
 					else
 						list_.emplace(iterator_at(pos));
diff --git a/source/paint/graphics.cpp b/source/paint/graphics.cpp
index 6cbfe571..684a8ca2 100644
--- a/source/paint/graphics.cpp
+++ b/source/paint/graphics.cpp
@@ -140,13 +140,13 @@ namespace paint
 
 		unsigned font::height() const
 		{
-			if(empty()) return false;
+			if(empty()) return 0;
 			return (impl_->font_ptr->height);
 		}
 
 		unsigned font::weight() const
 		{
-			if(empty()) return false;
+			if(empty()) return 0;
 			return (impl_->font_ptr->weight);
 		}
 
@@ -413,7 +413,7 @@ namespace paint
 
 		nana::size	graphics::text_extent_size(const std::wstring& text)	const
 		{
-			return text_extent_size(text.c_str(), static_cast<unsigned>(text.length()));
+			return text_extent_size(text.c_str(), text.length());
 		}
 
 		nana::size	graphics::text_extent_size(const wchar_t* str, std::size_t len)	const