Fixed an error when an owned window activates its owner during
creation.

diff --git a/windows/winpos.c b/windows/winpos.c
index 2d5c5f1..a16b009 100644
--- a/windows/winpos.c
+++ b/windows/winpos.c
@@ -1640,6 +1640,7 @@
 
         /* owned popups imply owner activation - not sure */
     if ((wndPtr->dwStyle & WS_POPUP) && wndPtr->owner &&
+        (wndPtr->owner->dwStyle & WS_VISIBLE ) &&
         !(wndPtr->owner->dwStyle & WS_DISABLED ))
     {
         if (!(wndPtr = wndPtr->owner)) return FALSE;