diff --git a/PowerEditor/src/NppBigSwitch.cpp b/PowerEditor/src/NppBigSwitch.cpp
index 6efa5a1a7..b7cab3084 100644
--- a/PowerEditor/src/NppBigSwitch.cpp
+++ b/PowerEditor/src/NppBigSwitch.cpp
@@ -650,8 +650,8 @@ LRESULT Notepad_plus::process(HWND hwnd, UINT message, WPARAM wParam, LPARAM lPa
 
 		case NPPM_INTERNAL_CHANGETABBAEICONS:
 		{
-			_mainDocTab.changeIcons(lParam);
-			_subDocTab.changeIcons(lParam);
+			_mainDocTab.changeIcons(static_cast<unsigned char>(lParam));
+			_subDocTab.changeIcons(static_cast<unsigned char>(lParam));
 			return TRUE;
 		}
 
diff --git a/PowerEditor/src/ScitillaComponent/DocTabView.h b/PowerEditor/src/ScitillaComponent/DocTabView.h
index b714e2e81..4abb3ea95 100644
--- a/PowerEditor/src/ScitillaComponent/DocTabView.h
+++ b/PowerEditor/src/ScitillaComponent/DocTabView.h
@@ -45,7 +45,7 @@ public :
 		TabBarPlus::destroy();
 	};
 
-	void init(HINSTANCE hInst, HWND parent, ScintillaEditView * pView, std::vector<IconList *> pIconListVector, size_t indexChoice) {
+	void init(HINSTANCE hInst, HWND parent, ScintillaEditView * pView, std::vector<IconList *> pIconListVector, unsigned char indexChoice) {
 		TabBarPlus::init(hInst, parent);
 		_pView = pView;
 
@@ -64,7 +64,7 @@ public :
 		return;
 	};
 
-	void changeIcons(size_t choice) {
+	void changeIcons(unsigned char choice) {
 		if (choice >= _pIconListVector.size())
 			return;
 		_iconListIndexChoice = choice;