gitk dev branch: F5 problem again

[Johannes Sixt <j.sixt@viscovery.net>]

I'm using gitk's dev branch (476ca63d Index [fnvr]highlights by id...) on
Windows.

Start gitk like this:

   gitk somefile.c

while on a branch whose tip touches somefile.c.

Now:

   git commit --amend

Then press F5 in gitk. I get these error reports after which gitk is
unresponsive:

can't read "children(1,)": no such element in array
can't read "children(1,)": no such element in array
    while executing
"lindex $children($curview,$id) 0"
    (procedure "ordertoken" line 15)
    invoked from within
"ordertoken $id"
    (procedure "idcol" line 2)
    invoked from within
"idcol $idlist $id"
    (procedure "layoutrows" line 51)
    invoked from within
"layoutrows $rl1 $r"
    (procedure "drawcommits" line 36)
    invoked from within
"drawcommits $row $endrow"
    (procedure "drawvisible" line 51)
    invoked from within
"drawvisible"
    (procedure "scrollcanv" line 3)
    invoked from within
"scrollcanv .tf.histframe.csb 0.00852273 0.146591"


... same as above ...
"drawvisible"
    (procedure "scrollcanv" line 3)
    invoked from within
"scrollcanv .tf.histframe.csb 0.0170455 0.155114"


... same as above ...
"drawvisible"
    ("eval" body line 1)
    invoked from within
"eval $script"
    (procedure "dorunq" line 9)
    invoked from within
"dorunq"
    ("after" script)


-- Hannes