diff --git a/twander.py b/twander.py
index a9de5b8..b2bf0df 100755
--- a/twander.py
+++ b/twander.py
@@ -4,7 +4,7 @@
 # For Updates See:  http://www.tundraware.com/Software/twander
 
 PROGNAME = "twander"
-RCSID = "$Id: twander.py,v 2.66 2003/01/17 20:58:49 tundra Exp $"
+RCSID = "$Id: twander.py,v 2.67 2003/01/17 21:37:22 tundra Exp $"
 VERSION = RCSID.split()[2]
 
 
@@ -172,6 +172,7 @@
 DEBUGLEVEL   = 0                # No debug output
 NODETAILS    = FALSE            # TRUE means details can never be displayed
 NONAVIGATE   = FALSE            # TRUE means that all directory navigation is prevented
+USETHREADS   = TRUE             # Use threads on Unix
 WARN         = TRUE             # Warnings on
 
 #####
@@ -1745,6 +1746,8 @@
     if dir:
         LoadDirList(dir)
 
+    # Inhibit further processing of key - some Function Keys
+    # have default behavior in Tk which we want to suppress.
     return "break"
 
 # End of 'FuncKeypress()'
@@ -1810,7 +1813,10 @@
         # Normal command execution for both Unix and Win32
         else:
             try:
-                thread.start_new_thread(os.system, (newcmd,))
+                if (OSNAME == 'posix') and not USETHREADS:
+                    os.system(newcmd)
+                else:
+                    thread.start_new_thread(os.system, (newcmd,))
             except:
                 WrnMsg(wBADEXE % newcmd)
 
@@ -2595,7 +2601,8 @@
 
 # Options (and their default values) which can be set in the configuration file
 
-UI.OptionsBoolean = {"AUTOREFRESH":AUTOREFRESH, "NODETAILS":NODETAILS, "NONAVIGATE":NONAVIGATE, "WARN":WARN}
+UI.OptionsBoolean = {"AUTOREFRESH":AUTOREFRESH, "NODETAILS":NODETAILS, "NONAVIGATE":NONAVIGATE,
+                     "USETHREADS":USETHREADS, "WARN":WARN}
 
 UI.OptionsNumeric = {"DEBUGLEVEL":DEBUGLEVEL, "FSZ":FSZ, "HEIGHT":HEIGHT, "MAXDIR":MAXDIR,
                      "MAXHIST":MAXHIST, "MAXNESTING":MAXNESTING, "REFRESHINT":REFRESHINT, "WIDTH":WIDTH}