From 41bcfa66e0633a8967063090b4811d93d286208f Mon Sep 17 00:00:00 2001
From: sls <sls>
Date: Wed, 21 Jun 1995 21:54:31 +0000
Subject: [PATCH] (get_class): check to make sure window still exists.

---
 windows_info.tcl | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/windows_info.tcl b/windows_info.tcl
index f005d77..64b02ae 100644
--- a/windows_info.tcl
+++ b/windows_info.tcl
@@ -38,6 +38,14 @@ object_class windows_info {
     }
     method get_class {target w} {
 	if ![info exists slot($w.class)] {
+	    if ![send $target winfo exists $w] {
+		# the window no longer exists, so delete it from our list
+		set ndx [lsearch -exact $slot(windows) $w]
+		if {$ndx >= 0} {
+		    set slot(windows) [lreplace $slot(windows) $ndx $ndx]
+		}
+		return ""
+	    }
 	    set slot($w.class) [send $target [list winfo class $w]]
 	}
 	return $slot($w.class)
-- 
2.23.0