Genbu series release 6a

7.1.783

• [Visualizer-global-tool]
• [BUGFIX] Don't NRE when cancelling a File Open dialog when Avalonia uses its GTK binding (Linux)
• Support font selection on Windows natively (monospace fonts only)
• On non-Windows platforms, if Tcl/Tk wish is present, use that to perform font selection (choose wisely)