[en] The future GSI Online-Offline-Object-Oriented analysis framework Go4 based on ROOT [CERN, R.Brun et al] provides a mechanism to monitor and control an analysis at any time. This is achieved by running the GUI and the analysis in different tasks. To control these tasks by one non-blocking GUI, the Go4 TaskHandler package was developed. It offers an asynchronous inter task communication via independent channels for commands, data, and status information. Each channel is processed by a dedicated thread and has a buffer queue as interface to the working thread. The threads are controlled by the Go4ThreadManager package, based on the ROOT TThread package. In parallel to the GUI actions, the analysis tasks can display objects like histograms in the GUI. A test GUI was implemented using the Qt widget library (Trolltech Inc.). A Qt to ROOT interface has been developed. The Go4 packages may be utilized for any ROOT application that requires to control independent data processing or monitoring tasks from a non-blocking GUI