diff --git a/common/sysutils.c b/common/sysutils.c
index 21b6eefb2..c30f9a0ce 100644
--- a/common/sysutils.c
+++ b/common/sysutils.c
@@ -778,8 +778,12 @@ gnupg_allow_set_foregound_window (pid_t pid)
   else if (inhibit_set_foregound_window)
     ;
   else if (!AllowSetForegroundWindow ((pid_t)pid == (pid_t)(-1)?ASFW_ANY:pid))
-    log_info ("AllowSetForegroundWindow(%lu) failed: %s\n",
-               (unsigned long)pid, w32_strerror (-1));
+    {
+      char *flags = getenv ("GNUPG_EXEC_DEBUG_FLAGS");
+      if (flags && (atoi (flags) & 2))
+        log_info ("AllowSetForegroundWindow(%lu) failed: %s\n",
+                  (unsigned long)pid, w32_strerror (-1));
+    }
 #endif
 }
 
diff --git a/doc/gpg.texi b/doc/gpg.texi
index ca5a4c4de..5c5bab6e5 100644
--- a/doc/gpg.texi
+++ b/doc/gpg.texi
@@ -3954,6 +3954,12 @@ Operation is further controlled by a few environment variables:
   under operating systems without proper support to figure out the
   name of a process' text file.
 
+  @item GNUPG_EXEC_DEBUG_FLAGS
+  @efindex GNUPG_EXEC_DEBUG_FLAGS
+  This variable allows to enable diagnostics for process management.
+  A numeric decimal value is expected.  Bit 0 enables general
+  diagnostics, bit 1 enables certain warnings on Windows.
+
 @end table
 
 When calling the gpg-agent component @command{@gpgname} sends a set of