Hello esteemed monks,

I have an weird problem with a Perl-Tk app that uses Tk::JComboBox v1.14 widgets. First time when I try changing state from 'disabled' to 'normal' to a JComboBox widget it throws an error like this:

Tk::Error: Can't set -state to `normal' for
Tk::JComboBox=HASH(0x84da458): Cannot use undef value for object of
type 'color' at /usr/lib/perl5/site_perl/5.10.0/Tk/JComboBox.pm line
1061.
...
[download]

But it does set state to normal, and after that, it's working fine and doesn't throw any errors when alternatively clicking on buttons.

I suspect it might be a installation specific error, but it appears on two on my Linux boxes with Perl 5.10.0 on Slackware 12.2 respectively 13.0 (but not on WindowsXP, with same Perl version).

Here is a similar, in behaviour, code using a single widget:

#!/usr/bin/perl

use strict;
use warnings;

use Tk;
use Tk::JComboBox;

my $mw = MainWindow->new;

my $jcb = $mw->JComboBox(
    # -state      => 'disabled',
    -entrywidth => 15,
    -choices => [
        {-name => 'one', -value => 1},
        {-name => 'two', -value => 2},
        "three",
    ],
)->pack;

my $chstate_n = $mw->Button(
    -text => 'normal',
    -command => sub {
        ch_state_normal();
    },
)->pack;

my $chstate_d = $mw->Button(
    -text => 'disable',
    -command => sub {
        ch_state_disabled();
    },
)->pack;

MainLoop;

sub ch_state_normal {
    print " normal\n";
    $jcb->configure(
        -state => 'normal',
    );
}

sub ch_state_disabled {
    print " disabled\n";
    $jcb->configure(
        -state => 'disabled',
    );
}
[download]

Does anybody else see the same behaviour? Thank you!

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.