diff --git a/button_windows.c b/button_windows.c
index 39fb8e0a..0c9dafd5 100644
--- a/button_windows.c
+++ b/button_windows.c
@@ -23,6 +23,13 @@ static BOOL onWM_NOTIFY(uiControl *c, WPARAM wParam, LPARAM lParam, void *data,
 	return FALSE;
 }
 
+static void onWM_DESTROY(uiControl *c, void *data)
+{
+	struct button *b = (struct button *) data;
+
+	uiFree(b);
+}
+
 // from http://msdn.microsoft.com/en-us/library/windows/desktop/dn742486.aspx#sizingandspacing
 #define buttonHeight 14
 
@@ -70,7 +77,8 @@ uiControl *uiNewButton(const char *text)
 	p.hInstance = hInstance;
 	p.onWM_COMMAND = onWM_COMMAND;
 	p.onWM_NOTIFY = onWM_NOTIFY;
-	p.onCommandNotifyData = b;
+	p.onWM_DESTROY = onWM_DESTROY;
+	p.onCommandNotifyDestroyData = b;
 	p.preferredSize = preferredSize;
 	p.data = b;
 	b->c = uiWindowsNewControl(&p);
diff --git a/newcontrol_windows.c b/newcontrol_windows.c
index eff4c9ad..98956faf 100644
--- a/newcontrol_windows.c
+++ b/newcontrol_windows.c
@@ -8,7 +8,8 @@ struct uiSingleHWNDControl {
 	HWND hwnd;
 	BOOL (*onWM_COMMAND)(uiControl *, WPARAM, LPARAM, void *, LRESULT *);
 	BOOL (*onWM_NOTIFY)(uiControl *, WPARAM, LPARAM, void *, LRESULT *);
-	void *onCommandNotifyData;
+	void (*onWM_DESTROY)(uiControl *, void *);
+	void *onCommandNotifyDestroyData;
 	void (*preferredSize)(uiControl *, int, int, LONG, intmax_t *, intmax_t *);
 	void *data;
 };
@@ -56,16 +57,18 @@ static LRESULT CALLBACK singleSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
 
 	switch (uMsg) {
 	case msgCOMMAND:
-		if ((*(c->onWM_COMMAND))((uiControl *) c, wParam, lParam, c->onCommandNotifyData, &lResult) != FALSE)
+		if ((*(c->onWM_COMMAND))((uiControl *) c, wParam, lParam, c->onCommandNotifyDestroyData, &lResult) != FALSE)
 			return lResult;
 		break;
 	case msgNOTIFY:
-		if ((*(c->onWM_NOTIFY))((uiControl *) c, wParam, lParam, c->onCommandNotifyData, &lResult) != FALSE)
+		if ((*(c->onWM_NOTIFY))((uiControl *) c, wParam, lParam, c->onCommandNotifyDestroyData, &lResult) != FALSE)
 			return lResult;
 		break;
-	case WM_NCDESTROY:
-		// TODO call an onDestroy handler
+	case WM_DESTROY:
+		(*(c->onWM_DESTROY))((uiControl *) c, c->onCommandNotifyDestroyData);
 		uiFree(c);
+		break;
+	case WM_NCDESTROY:
 		if ((*fv_RemoveWindowSubclass)(hwnd, singleSubclassProc, uIdSubclass) == FALSE)
 			logLastError("error removing Windows control subclass in singleSubclassProc()");
 		break;
@@ -96,7 +99,8 @@ uiControl *uiWindowsNewControl(uiWindowsNewControlParams *p)
 
 	c->onWM_COMMAND = p->onWM_COMMAND;
 	c->onWM_NOTIFY = p->onWM_NOTIFY;
-	c->onCommandNotifyData = p->onCommandNotifyData;
+	c->onWM_DESTROY = p->onWM_DESTROY;
+	c->onCommandNotifyDestroyData = p->onCommandNotifyDestroyData;
 	c->preferredSize = p->preferredSize;
 
 	c->data = p->data;
diff --git a/ui_windows.h b/ui_windows.h
index cbbe8596..c86e6a95 100644
--- a/ui_windows.h
+++ b/ui_windows.h
@@ -23,8 +23,10 @@ struct uiWindowsNewControlParams {
 	// 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.
 	BOOL (*onWM_COMMAND)(uiControl *c, WPARAM wParam, LPARAM lParam, void *data, LRESULT *lResult);
 	BOOL (*onWM_NOTIFY)(uiControl *c, WPARAM wParam, LPARAM lParam, void *data, LRESULT *lResult);
-	// This is the data parameter to both of the above.
-	void *onCommandNotifyData;
+	// This is called in WM_DESTROY.
+	void (*onWM_DESTROY)(uiControl *c, void *data);
+	// This is the data parameter to all three of the above.
+	void *onCommandNotifyDestroyData;
 
 	// This function is called when ui needs to know how to rearrange controls in a window.
 	// baseX and baseY are the base units used to convert between dialog units and pixels.