--- a/ui/win32/win32.c	Thu Oct 09 18:24:09 2025 +0200
+++ b/ui/win32/win32.c	Thu Oct 09 18:49:19 2025 +0200
@@ -35,7 +35,7 @@
 }
 
 void* w32_widget_create(W32WidgetClass *wclass, HWND hwnd, size_t obj_size) {
-    W32Widget *w = malloc(obj_size);
+    W32Widget *w = calloc(obj_size, 1);
     w->wclass = wclass;
     w->hwnd = hwnd;
     SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR)w);