diff --git a/gitk b/gitk
index 9ab6dbaa46..998a051942 100755
--- a/gitk
+++ b/gitk
@@ -5125,10 +5125,14 @@ proc drawvisible {} {
 proc clear_display {} {
     global iddrawn linesegs need_redisplay nrows_drawn
     global vhighlights fhighlights nhighlights rhighlights
+    global linehtag linentag linedtag
 
     allcanvs delete all
     catch {unset iddrawn}
     catch {unset linesegs}
+    catch {unset linehtag}
+    catch {unset linentag}
+    catch {unset linedtag}
     catch {unset vhighlights}
     catch {unset fhighlights}
     catch {unset nhighlights}