Corrected problem caused by adding a scrollbar to the parameters

window in the toolkit, which was to the "tkwait" command, which
waits for a change in state.  What was intended was to wait for
a change in state to visible only;  once visible, the "tkwait"
command should not invoked or else the process will block.

VERSION

@@ -1 +1 @@
-8.3.384
+8.3.385

tcltk/toolkit.tcl

@@ -1443,7 +1443,9 @@ proc magic::gencell_dialog {instname gencell_type library parameters} {
    raise .params
 
    # Wait for window to become visible to set the scroll region
-   tkwait visibility .params.body.area
+   if {[catch {winfo children .params.body.area}]} {
+      tkwait visibility .params.body.area
+   }
    .params.body.area config -scrollregion [.params.body.area bbox all]
 }