diff --git a/button_windows.c b/button_windows.c
index c57b7789..149c52b1 100644
--- a/button_windows.c
+++ b/button_windows.c
@@ -17,7 +17,7 @@ static BOOL onWM_COMMAND(uiControl *c, WORD code, LRESULT *lResult)
 	return TRUE;
 }
 
-static BOOL onWM_NOTIFY(uiControl *c, WPARAM wParam, LPARAM lParam, LRESULT *lResult)
+static BOOL onWM_NOTIFY(uiControl *c, NMHDR *nm, LRESULT *lResult)
 {
 	return FALSE;
 }
diff --git a/checkbox_windows.c b/checkbox_windows.c
index abe128d5..4f903ef9 100644
--- a/checkbox_windows.c
+++ b/checkbox_windows.c
@@ -27,7 +27,7 @@ static BOOL onWM_COMMAND(uiControl *c, WORD code, LRESULT *lResult)
 	return TRUE;
 }
 
-static BOOL onWM_NOTIFY(uiControl *c, WPARAM wParam, LPARAM lParam, LRESULT *lResult)
+static BOOL onWM_NOTIFY(uiControl *c, NMHDR *nm, LRESULT *lResult)
 {
 	return FALSE;
 }
diff --git a/entry_windows.c b/entry_windows.c
index df4a91d7..41614c5d 100644
--- a/entry_windows.c
+++ b/entry_windows.c
@@ -9,7 +9,7 @@ static BOOL onWM_COMMAND(uiControl *c, WORD code, LRESULT *lResult)
 	return FALSE;
 }
 
-static BOOL onWM_NOTIFY(uiControl *c, WPARAM wParam, LPARAM lParam, LRESULT *lResult)
+static BOOL onWM_NOTIFY(uiControl *c, NMHDR *nm, LRESULT *lResult)
 {
 	return FALSE;
 }
diff --git a/newcontrol_windows.c b/newcontrol_windows.c
index f95f67f9..0122db73 100644
--- a/newcontrol_windows.c
+++ b/newcontrol_windows.c
@@ -6,7 +6,7 @@ typedef struct singleHWND singleHWND;
 struct singleHWND {
 	HWND hwnd;
 	BOOL (*onWM_COMMAND)(uiControl *, WORD, LRESULT *);
-	BOOL (*onWM_NOTIFY)(uiControl *, WPARAM, LPARAM, LRESULT *);
+	BOOL (*onWM_NOTIFY)(uiControl *, NMHDR *, LRESULT *);
 	void (*onWM_DESTROY)(uiControl *);
 	uintptr_t parent;
 };
@@ -69,7 +69,7 @@ static LRESULT CALLBACK singleSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
 			return lResult;
 		break;
 	case msgNOTIFY:
-		if ((*(s->onWM_NOTIFY))(c, wParam, lParam, &lResult) != FALSE)
+		if ((*(s->onWM_NOTIFY))(c, (NMHDR *) lParam, &lResult) != FALSE)
 			return lResult;
 		break;
 	case WM_DESTROY:
diff --git a/ui_windows.h b/ui_windows.h
index b89af3af..cfea2877 100644
--- a/ui_windows.h
+++ b/ui_windows.h
@@ -22,9 +22,8 @@ struct uiWindowsNewControlParams {
 	// ui redirects the message back and calls these functions.
 	// Store the result in *lResult and return any non-FALSE value (such as TRUE) to return the given result; return FALSE to pass the notification up to your window procedure.
 	// Note that these are only issued if they come from the uiControl itself; notifications from children of the uiControl (such as a header control) will be received normally.
-	// TODO don't give WPARAM/LPARAM raw
 	BOOL (*onWM_COMMAND)(uiControl *c, WORD code, LRESULT *lResult);
-	BOOL (*onWM_NOTIFY)(uiControl *c, WPARAM wParam, LPARAM lParam, LRESULT *lResult);
+	BOOL (*onWM_NOTIFY)(uiControl *c, NMHDR *nm, LRESULT *lResult);
 	// This is called in WM_DESTROY.
 	void (*onWM_DESTROY)(uiControl *c);
 };