Bug in breakpoint window

[Tom Tromey <tromey at redhat dot com>]

If I bring up the breakpoint window I can double-click on a breakpoint
to have the location appear in the source window.  This is a nice
feature which I found by accident (maybe it should also appear on the
popup menu for a breakpoint?)

While this works, it also gives me an error.  Here is the Tcl stack
trace.

bad text index "4"
    while executing
"$win tag add $tag $linenum.0 $stop"
    (object "::.srcwin0.srcwin.container.pane2.childsite.con" method "::SrcTextWin::insertBreakTag" body line 31)
    invoked from within
"insertBreakTag $win $linenum $tag_type"
    (object "::.srcwin0.srcwin.container.pane2.childsite.con" method "::SrcTextWin::do_bp" body line 90)
    invoked from within
"do_bp $twin $action $linenum $type $bpnum $enabled $thread 0"
    ("SOURCE" arm line 3)
    invoked from within
"switch $current(mode) {
    SOURCE {
      if {[string compare $file $current(filename)] == 0 && $linenum != {}} {
	do_bp $twin $action $linenum $type..."
    (object "::.srcwin0.srcwin.container.pane2.childsite.con" method "::SrcTextWin::bp" body line 4)
    invoked from within
"bp create $bpnum $addr $line $file $type $enabled"
    (object "::.srcwin0.srcwin.container.pane2.childsite.con" method "::SrcTextWin::display_breaks" body line 30)
    invoked from within
"display_breaks"
    (object "::.srcwin0.srcwin.container.pane2.childsite.con" method "::SrcTextWin::location" body line 69)
    invoked from within
"$twin location $tag $name $funcname $line $addr $pc_addr $lib"
    (object "::.srcwin0.srcwin" method "::SrcWin::location" body line 52)
    invoked from within
"$window location $tag $linespec"
    (procedure "::SrcWin::choose_and_display" body line 4)
    invoked from within
"SrcWin::choose_and_display BROWSE_TAG [gdb_loc *$pc]"
    (object "::.bpwin0.bpwin" method "::BpWin::goto_bp" body line 10)
    invoked from within
"::.bpwin0.bpwin goto_bp 1"
    (command bound to event)errorCode is NONE

Tom