--- \dll\iup\a\src\win\iupwin_toggle.c	Mon Aug 20 06:57:56 2018
+++ iupwin_toggle.c	Sat May 25 10:17:01 2019
@@ -578,6 +578,7 @@
   case BN_DOUBLECLICKED:
     if (iupAttribGetBoolean(ih, "IGNOREDOUBLECLICK"))
       return 0;
+    /* FALLTHROUGH */
   case BN_CLICKED:
     {
       Ihandle *radio;