diff --git a/sane/DlgCfgMgr.cpp b/sane/DlgCfgMgr.cpp
index a1b98e6..5ff5cd0 100644
--- a/sane/DlgCfgMgr.cpp
+++ b/sane/DlgCfgMgr.cpp
@@ -206,8 +206,9 @@ void dlg_cfg_mgr::on_del_selected(void)
 void dlg_cfg_mgr::on_del_all(void)
 {
 	cfg_->remove_all_schemes();
-	ListView_DeleteAllItems(get_item(IDC_LIST1));
+	ListView_DeleteAllItems(get_item(IDC_LIST1));	// clear list
 	schm_changed_ = true;
+	dlg_base::set_item_text(IDC_EDIT1, L"");
 }
 bool dlg_cfg_mgr::is_scheme_changed(void)
 {
diff --git a/sane/DlgCfgMgr.h b/sane/DlgCfgMgr.h
index 6262fce..ef66783 100644
--- a/sane/DlgCfgMgr.h
+++ b/sane/DlgCfgMgr.h
@@ -15,7 +15,7 @@ class dlg_cfg_mgr: public dlg_base
 {
 	gb::scanner_cfg*	cfg_;
 	std::wstring		label_;
-	bool				schm_changed_;
+	bool				schm_changed_;	// to notify parent refreshing UI and settings
 
 	BOOL handle_message(UINT msg, WPARAM wp, LPARAM lp) override;
 	void handle_command(WORD code, WORD id, HANDLE ctrl);
diff --git a/sane/DlgSetting.cpp b/sane/DlgSetting.cpp
index e894500..ebbae8c 100644
--- a/sane/DlgSetting.cpp
+++ b/sane/DlgSetting.cpp
@@ -130,7 +130,7 @@ void dlg_setting::handle_command(WORD code, WORD id, HANDLE ctrl)
 					}
 					n->release();
 				}
-				s->end_setting(true);
+				s->end_setting(true);	// discard changes in prev-scheme
 				s->release();
 			}
 		}
@@ -144,7 +144,7 @@ void dlg_setting::handle_command(WORD code, WORD id, HANDLE ctrl)
 				gb::sane_config_schm* s = cfg_->get_scheme();
 				if (s)
 				{
-					s->end_setting(false);
+					s->end_setting(false); 	// save changes
 					s->release();
 				}
 
@@ -196,7 +196,7 @@ void dlg_setting::handle_command(WORD code, WORD id, HANDLE ctrl)
 	{
 		dlg_cfg_mgr	dlg(cfg_, hwnd());
 		dlg.do_modal(hwnd());
-		if (dlg.is_scheme_changed())
+		if (dlg.is_scheme_changed())	// refresh settings and UI
 		{
 			gb::sane_config_schm* schm = cfg_->get_scheme();
 			apply_scheme_(schm, apply_param_);
diff --git a/twain/twain/huagaods.cpp b/twain/twain/huagaods.cpp
index d05a3df..95c41f0 100644
--- a/twain/twain/huagaods.cpp
+++ b/twain/twain/huagaods.cpp
@@ -28,7 +28,7 @@ using namespace std::placeholders;
 
 extern HMODULE me_;
 
-// WIA COM:	IStiUSD & IWiaMiniDrv
+// WIA COM:	IStiUSD & IWiaMiniDrv 
 
 //custom define caps enum
 enum CapTypeEx : unsigned short {