diff --git a/frontend/xorriso-tcltk b/frontend/xorriso-tcltk
index 08dd318b..f7ec5ed6 100755
--- a/frontend/xorriso-tcltk
+++ b/frontend/xorriso-tcltk
@@ -2664,7 +2664,6 @@ proc set_display_msg {mode} {
 
 
 # Display a frontend error message in the .msglist box and by a pop-up window.
-# >>> It would be nice to be able to wait for user confirmation.
 #
 proc xorriso_tcltk_errmsg {msg} {
   global highest_cmd_sev_msg
@@ -2716,6 +2715,7 @@ proc destroy_yesno {w answer} {
 
   if {$w != ""} {
     set yesno_window_geometry [wm geometry $w]
+    grab release $w
     destroy $w
   }
   set yesno_window_is_active 0
@@ -2737,6 +2737,9 @@ proc window_yesno {question} {
   global answer_of_yesno yesno_window_is_active yesno_window_geometry
 
   set w {.yesno_window}
+  if {"$yesno_window_is_active" == 1} {
+    set yesno_window_is_active [window_exists $w]
+  }
   if {"$yesno_window_is_active" == 1} {
     raise $w
     xorriso_tcltk_errmsg "xorriso-tcltk : SORRY : You still need to answer an older yes/no question"
@@ -2750,11 +2753,14 @@ proc window_yesno {question} {
   label $w.question -text "$question"
   button $w.yes -text "yes" -command "destroy_yesno $w 1" \
                 -borderwidth 4 -padx 20 -pady 20
+  bind_help $w.yes "yes/no"
   button $w.no -text "no" -command "destroy_yesno $w 0" \
                 -borderwidth 4 -padx 20 -pady 20
+  bind_help $w.no "yes/no"
   pack $w.yes $w.question $w.no -side left
   update idletasks
 
+  grab set $w
   tkwait variable answer_of_yesno
   return "$answer_of_yesno"
 }
@@ -2768,6 +2774,9 @@ proc window_yesno_ever {question} {
   global yesno_to_all
 
   set w {.yesno_window}
+  if {"$yesno_window_is_active" == 1} {
+    set yesno_window_is_active [window_exists $w]
+  }
   if {"$yesno_window_is_active" == 1} {
     raise $w
     xorriso_tcltk_errmsg "xorriso-tcltk : SORRY : You still need to answer an older yes/no question"
@@ -2802,6 +2811,7 @@ proc window_yesno_ever {question} {
                 -in $w -side left -expand 1 -fill both
   update idletasks
 
+  grab set $w
   tkwait variable answer_of_yesno
   return "$answer_of_yesno"
 }
@@ -2816,11 +2826,13 @@ proc reset_yesno_to_all {} {
 
 # Destroy the notification pop-up window.
 #
-proc destroy_ack {w} {
+proc destroy_ack {w had_focus} {
   global ack_window_is_active ack_window_geometry
 
   if {"$w" != ""} {
     set ack_window_geometry [wm geometry $w]
+    grab release $w
+    focus "$had_focus"
     destroy "$w"
   }
   set ack_window_is_active 0
@@ -2831,13 +2843,18 @@ proc destroy_ack {w} {
 #
 proc window_ack {question button_color where} {
   global answer_of_yesno ack_window_is_active ack_window_geometry
+  global continue_from_ack
 
+  set had_focus [focus]
   set re_use_widgets 0
   if {"$where" == "embedded"} {
     set w ""
     set destroy_cmd ""
   } else {
     set w {.ack_window}
+    if {"$ack_window_is_active" == 1} {
+      set ack_window_is_active [window_exists $w]
+    }
     if {"$ack_window_is_active" == 0} {
       toplevel $w -borderwidth 20 -class Dialog
       wm title $w "xorriso-tcltk acknowledge"
@@ -2846,7 +2863,7 @@ proc window_ack {question button_color where} {
       set re_use_widgets 1
     }
     set_window_position $w "$ack_window_geometry"
-    set destroy_cmd "destroy_ack $w"
+    set destroy_cmd "destroy_ack $w $had_focus"
   }
   if {"$re_use_widgets" == 1} {
     $w.question configure -text "$question"
@@ -2855,12 +2872,15 @@ proc window_ack {question button_color where} {
     label $w.question -text "$question"
     button $w.ok -text "Continue" -command "$destroy_cmd" \
                  -background "$button_color"
+    bind $w.ok <Return> "$destroy_cmd"
+    bind_help $w.ok "Continue"
     pack $w.question -side top -expand 1 -fill both
     pack $w.ok -side top 
   }
 
-  # >>> How to block any event but the "Continue" button ?
-
+  focus $w.ok
+  grab set $w
+  tkwait variable ack_window_is_active
 }
 
 
@@ -2917,6 +2937,9 @@ proc window_help {about_what button_color} {
     set old_geometry "$help_window_geometry"
     set window_lines "$help_window_lines"
   }
+  if {"$window_is_active" == 1} {
+    set window_is_active [window_exists $w]
+  }
 
   # Giving the help text some distance from the border decorations
   set line_width 82
@@ -2935,6 +2958,32 @@ proc window_help {about_what button_color} {
       set old_geometry "$help_window_geometry"
     }
   }
+  # Dealing with initiating windows that are grabbed
+  set grabbed [grab current]
+  if {$grabbed == ""} {set grabbed "-"}
+  if {$grabbed != "-" && $window_is_active == 1} {
+     destroy_help $w "$help_main"
+     set window_is_active 0
+  }
+  if {$grabbed != "-"} {
+    # Set old_geometry to position underneath grabbed window
+    set value [wm geometry $grabbed]
+    set idx [string first "+" $value]
+    set height_idx [string first "x" $value]
+    if {$idx != -1 && $height_idx != -1 && $idx > $height_idx} {
+      set width [string range $value 0 [expr $height_idx-1]]
+      set height [string range $value [expr $height_idx+1] [expr $idx-1]]
+      set x [string range $value [expr $idx+1] end]
+      set idx [string first "+" $x]
+      if {"$idx" != -1} {
+        set y [string range $x [expr $idx+1] end]
+        set x [string range $x 0 [expr $idx-1]]
+        set y [expr $y+$height]
+        set old_geometry "${width}x${height}+${x}+${y}"
+      }
+    }
+  }
+
   set re_use_widgets 0
   if {"$window_is_active" == 0} {
     toplevel $w -borderwidth "$help_window_border_width" -class Help
@@ -2951,6 +3000,7 @@ proc window_help {about_what button_color} {
   } else {
     set re_use_widgets 1
   }
+
   if {"$re_use_widgets" == 1} {
     $w.text configure -state normal
     $w.text delete 1.0 end
@@ -3054,6 +3104,18 @@ proc reset_to_normal_background {w} {
 }
 
 
+# Checks whether a window is really there
+#
+proc window_exists {w} {
+  set window_exists 0
+  catch {
+    $w cget -background
+    set window_exists 1
+  }
+  return $window_exists
+}
+
+
 # ------ Building GUI components ------
 
 # ------ GUI layout parameters ------
@@ -4718,7 +4780,9 @@ about to overwrite a file object and more such overwrite situations are
 to be expected.
 
 If the button is clicked, then all further yes/no questions of that GUI
-action will be answered automatically with yes."
+action will be answered automatically with yes.
+
+[about_help_for_yesno]"
   }
   if {"$what" == "no to all"} {
     return \
@@ -4727,7 +4791,30 @@ about to overwrite a file object and more such overwrite situations are
 to be expected.
 
 If the button is clicked, then all further yes/no questions of that GUI
-action will be answered automatically with no."
+action will be answered automatically with no.
+
+[about_help_for_yesno]"
+  }
+  if {"$what" == "Continue"} {
+    return \
+"The \"Continue\" button appears in the notification windows which tell
+about a failed or rejected GUI action.
+
+---------------------------------------------------------------------------
+
+It is impossible to trigger any further GUI action while the notification
+window is displayed. You either have to click the \"Continue\" button
+or hit the Return key.
+
+You cannot even close this help window before you did that."
+  }
+  if {"$what" == "yes/no"} {
+    return \
+"The \"yes\" and \"no\" buttons appear in the confirmation window which tells
+about a potentially dangerous GUI action and demands a user decision whether
+to really perform this action.
+
+[about_help_for_yesno]"
   }
 
   return "--- No help text found for topic '$what'"
@@ -4772,6 +4859,18 @@ the associated text field, but does not hit the Return key.
 }
 
 
+# Tell about pecliarity of help window triggered by yes/no window
+proc about_help_for_yesno {} {
+  return \
+"---------------------------------------------------------------------------
+
+It is impossible to trigger any further GUI action while the confirmation
+window is displayed. You have to click one of the buttons in that window.
+
+You cannot even close this help window before you clicked one of the buttons."
+}
+
+
 # ------- Misc helper procedures -------
 
 
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index bb526c46..cd9f8af8 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2013.01.03.102627"
+#define Xorriso_timestamP "2013.01.03.125535"