<s>
A	O
paned	O
window	O
is	O
a	O
windows	O
(	O
or	O
build-ups	O
)	O
in	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
that	O
has	O
multiple	O
parts	O
,	O
layers	O
,	O
or	O
sections	O
.	O
</s>
<s>
Examples	O
of	O
this	O
include	O
a	O
code	B-Application
browser	I-Application
in	O
a	O
typical	O
integrated	B-Application
development	I-Application
environment	I-Application
;	O
a	O
file	B-Application
browser	I-Application
with	O
multiple	O
panels	O
;	O
or	O
a	O
web	O
page	O
that	O
contains	O
multiple	O
frames	O
.	O
</s>
<s>
The	O
term	O
task	O
pane	O
is	O
used	O
by	O
Microsoft	O
to	O
identify	O
any	O
area	O
cordoned	O
off	O
from	O
the	O
main	O
screen	B-Device
area	O
of	O
an	O
application	O
and	O
used	O
for	O
a	O
specific	O
function	O
,	O
such	O
as	O
changing	O
the	O
displayed	O
font	O
in	O
a	O
word	O
processor	O
.	O
</s>
<s>
A	O
Three-pane	B-Application
interface	I-Application
is	O
a	O
category	O
of	O
graphical	B-Application
user	I-Application
interface	I-Application
in	O
which	O
the	O
screen	B-Device
or	O
window	O
is	O
divided	O
into	O
three	O
panes	O
displaying	O
information	O
.	O
</s>
<s>
This	O
information	O
typically	O
falls	O
into	O
a	O
hierarchal	O
relationship	O
of	O
master-detail	B-Application
with	O
an	O
embedded	O
inspector	O
window	O
.	O
</s>
<s>
Microsoft	O
's	O
Outlook	B-Application
Express	I-Application
email	B-Protocol
client	I-Protocol
popularized	O
a	O
mailboxes	O
/	O
mailbox	O
contents	O
/	O
email	O
text	O
layout	O
that	O
became	O
the	O
norm	O
until	O
web-based	O
user	O
interfaces	O
rose	O
in	O
popularity	O
during	O
the	O
mid-2000s	O
.	O
</s>
<s>
Even	O
today	O
,	O
many	O
webmail	B-Protocol
scripts	O
emulate	O
this	O
interface	O
style	O
.	O
</s>
