merge 8.6

1 files changed, 12 insertions, 3 deletions

diff --git a/library/ttk/treeview.tcl b/library/ttk/treeview.tcl
index 4158739..df188b7 100644
--- a/library/ttk/treeview.tcl
+++ b/library/ttk/treeview.tcl
@@ -120,9 +120,18 @@ proc ttk::treeview::ActivateHeading {w heading} {
     variable State
 
     if {$w != $State(activeWidget) || $heading != $State(activeHeading)} {
-	if {[winfo exists $State(activeWidget)] && $State(activeHeading) != {}
-	        && $State(activeHeading) in [$State(activeWidget) cget -displaycolumns]} {
-	    $State(activeWidget) heading $State(activeHeading) state !active
+	if {[winfo exists $State(activeWidget)] && $State(activeHeading) != {}} {
+	    # It may happen that $State(activeHeading) no longer corresponds
+	    # to an existing display column. This happens for instance when
+	    # changing -displaycolumns in a bound script when this change
+	    # triggers a <Leave> event. A proc checking if the display column
+	    # $State(activeHeading) is really still present or not could be
+	    # written but it would need to check several special cases:
+	    #   a. -displaycolumns "#all" or being an explicit columns list 
+	    #   b. column #0 display is not governed by the -displaycolumn
+	    #      list but by the value of the -show option
+	    # --> Let's rather catch the following line.
+	    catch {$State(activeWidget) heading $State(activeHeading) state !active}
 	}
 	if {$heading != {}} {
 	    $w heading $heading state active