Better error message.

scripts/tkremind.in

@@ -1978,7 +1978,7 @@ proc CreateModifyDialog {w day firstDay args} {
     pack $w.labhol $w.issue $w.skip $w.before $w.after -side top -anchor w -in $w.hol
 
     # TEXT ENTRY
-    label $w.msglab -text "Summary (required): "
+    label $w.msglab -text "Summary: "
     entry $w.entry
     balloon_add_help $w.entry "Enter the text of the reminder (required)"
     grid $w.msglab -row 0 -column 0 -in $w.msg -sticky e
@@ -2296,7 +2296,7 @@ proc CreateReminder {w} {
     set body [string trim [$w.entry get]]
 
     if {"$body" == ""} {
-	error "Blank body in reminder"
+	error "Summary is required"
     }
 
     set DidOmit 0