gitk: Fix error message when clicking on a connecting line

diff --git a/gitk b/gitk
index 54cffde7214b101b677558e3b4935de2a86d83ed..a569c0d4b8a7616fdf0651251a021a5e03015501 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -7970,6 +7970,8 @@ proc changediffdisp {} {
 proc highlightfile {cline} {
     global cflist cflist_top
 
+    if {![info exists cflist_top]} return
+
     $cflist tag remove highlight $cflist_top.0 "$cflist_top.0 lineend"
     $cflist tag add highlight $cline.0 "$cline.0 lineend"
     $cflist see $cline.0