This work explores Tcl-Tk 8.0 as a tool to easily build script based GUIs for Ada95 realtime systems. Tcl-Tk 8.0 is a library that makes graphic programming easier, but it suffers from being not thread-safe. TASH is a thick binding that allows Ada95 single threaded code to use Tcl-Tk. An application architecture is proposed, the deferred server, that provides transparent use of Tcl-Tk to multithreaded Ada95 applications vía TASH. We've found that only a minimal extension to Tcl-Tk 8.0 and TASH is required to support it, and a successful prototype has been implemented based on these ideas. Then, the early integration of Tcl-Tk graphic user interfaces in HRT-HOOD designs is investigated and, unfortunately, we conclude that this is not possible. However, a HRT-HOOD conform distributed configuration is outlined where the user interface becomes a multithreaded remote service based on the deferred server architecture.