<s>
A	O
window	B-Application
manager	I-Application
is	O
system	B-Application
software	I-Application
that	O
controls	O
the	O
placement	O
and	O
appearance	O
of	O
windows	O
within	O
a	O
windowing	B-Application
system	I-Application
in	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
.	O
</s>
<s>
Most	O
window	B-Application
managers	I-Application
are	O
designed	O
to	O
help	O
provide	O
a	O
desktop	B-Application
environment	O
.	O
</s>
<s>
They	O
work	O
in	O
conjunction	O
with	O
the	O
underlying	O
graphical	O
system	O
that	O
provides	O
required	O
functionality	O
—	O
support	O
for	O
graphics	O
hardware	O
,	O
pointing	B-Device
devices	I-Device
,	O
and	O
a	O
keyboard	O
—	O
and	O
are	O
often	O
written	O
and	O
created	O
using	O
a	O
widget	B-Library
toolkit	I-Library
.	O
</s>
<s>
Few	O
window	B-Application
managers	I-Application
are	O
designed	O
with	O
a	O
clear	O
distinction	O
between	O
the	O
windowing	B-Application
system	I-Application
and	O
the	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
Every	O
graphical	B-Application
user	I-Application
interface	I-Application
based	O
on	O
a	O
windows	B-Architecture
metaphor	I-Architecture
has	O
some	O
form	O
of	O
window	B-Application
management	I-Application
.	O
</s>
<s>
Elements	O
usually	O
associated	O
with	O
window	B-Application
managers	I-Application
allow	O
the	O
user	O
to	O
open	O
,	O
close	O
,	O
minimize	O
,	O
maximize	O
,	O
move	O
,	O
resize	O
,	O
and	O
keep	O
track	O
of	O
running	O
windows	O
,	O
including	O
window	O
decorators	O
.	O
</s>
<s>
Many	O
window	B-Application
managers	I-Application
also	O
come	O
with	O
various	O
utilities	O
and	O
features	O
such	O
as	O
task	O
bars	O
,	O
program	O
launchers	O
,	O
docks	O
to	O
facilitate	O
halving	O
or	O
quartering	O
windows	O
on	O
screen	O
,	O
workspaces	B-Application
for	O
grouping	O
windows	O
,	O
desktop	B-Application
icons	B-Device
,	O
wallpaper	O
,	O
an	O
ability	O
to	O
keep	O
select	O
windows	O
in	O
foreground	O
,	O
the	O
ability	O
to	O
"	O
roll	O
up	O
"	O
windows	O
to	O
show	O
only	O
their	O
title	O
bars	O
,	O
to	O
cascade	O
windows	O
,	O
to	O
stack	O
windows	O
into	O
a	O
grid	O
,	O
to	O
group	O
windows	O
of	O
the	O
same	O
program	O
in	O
the	O
task	O
bar	O
in	O
order	O
to	O
save	O
space	O
,	O
and	O
optional	O
multi-row	O
taskbars	O
.	O
</s>
<s>
In	O
1973	O
,	O
the	O
Xerox	B-Device
Alto	I-Device
became	O
the	O
first	O
computer	O
shipped	O
with	O
a	O
working	O
WIMP	B-Application
GUI	B-Application
.	O
</s>
<s>
It	O
used	O
a	O
stacking	B-Device
window	I-Device
manager	I-Device
that	O
allowed	O
overlapping	O
windows	O
.	O
</s>
<s>
While	O
it	O
is	O
unclear	O
if	O
Microsoft	B-Application
Windows	I-Application
contains	O
designs	O
copied	O
from	O
Apple	O
's	O
classic	B-Application
Mac	I-Application
OS	I-Application
,	O
it	O
is	O
clear	O
that	O
neither	O
was	O
the	O
first	O
to	O
produce	O
a	O
GUI	B-Application
using	O
stacking	B-Device
windows	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
the	O
Xerox	B-Operating_System
Star	I-Operating_System
,	O
successor	O
to	O
the	O
Alto	B-Device
,	O
used	O
tiling	O
for	O
most	O
main	O
application	O
windows	O
,	O
and	O
used	O
overlapping	O
only	O
for	O
dialogue	O
boxes	O
,	O
removing	O
most	O
of	O
the	O
need	O
for	O
stacking	B-Device
.	O
</s>
<s>
Mac	B-Application
OS	I-Application
was	O
one	O
of	O
the	O
earliest	O
commercially	O
successful	O
examples	O
of	O
a	O
GUI	B-Application
that	O
used	O
a	O
sort	O
of	O
stacking	B-Device
window	B-Application
management	I-Application
via	O
QuickDraw	B-Operating_System
.	O
</s>
<s>
Currently	O
macOS	B-Application
uses	O
a	O
somewhat	O
more	O
advanced	O
window	B-Application
manager	I-Application
that	O
has	O
supported	O
compositing	O
since	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.0	I-Operating_System
,	O
and	O
was	O
updated	O
in	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.2	I-Operating_System
to	O
support	O
hardware	O
accelerated	O
compositing	O
via	O
the	O
Quartz	O
Compositor	O
.	O
</s>
<s>
GEM	B-Application
1.1	I-Application
was	O
a	O
window	B-Application
manager	I-Application
that	O
supported	O
the	O
desktop	B-Application
metaphor	I-Application
,	O
and	O
used	O
stacking	B-Device
,	O
allowing	O
all	O
windows	O
to	O
overlap	O
.	O
</s>
<s>
GEM	B-Application
is	O
famous	O
for	O
having	O
been	O
included	O
as	O
the	O
main	O
GUI	B-Application
used	O
on	O
the	O
Atari	B-Device
ST	I-Device
,	O
which	O
ran	O
Atari	B-Application
TOS	I-Application
,	I-Application
and	O
was	O
also	O
a	O
popular	O
GUI	B-Application
for	O
MS-DOS	B-Application
prior	O
to	O
the	O
widespread	O
use	O
of	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
As	O
a	O
result	O
of	O
a	O
lawsuit	O
by	O
Apple	O
,	O
GEM	B-Application
was	O
forced	O
to	O
remove	O
the	O
stacking	B-Device
capabilities	O
,	O
making	O
it	O
a	O
tiling	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
During	O
the	O
mid-1980s	O
,	O
Amiga	B-Application
OS	I-Application
contained	O
an	O
early	O
example	O
of	O
a	O
compositing	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
called	O
Intuition	B-Application
(	O
one	O
of	O
the	O
low-level	O
libraries	O
of	O
AmigaOS	B-Application
,	O
which	O
was	O
present	O
in	O
Amiga	O
system	O
ROMs	B-Device
)	O
,	O
capable	O
of	O
recognizing	O
which	O
windows	O
or	O
portions	O
of	O
them	O
were	O
covered	O
,	O
and	O
which	O
windows	O
were	O
in	O
the	O
foreground	O
and	O
fully	O
visible	O
,	O
so	O
it	O
could	O
draw	O
only	O
parts	O
of	O
the	O
screen	O
that	O
required	O
refresh	O
.	O
</s>
<s>
Additionally	O
,	O
Intuition	B-Application
supported	O
compositing	O
.	O
</s>
<s>
The	O
Amiga	O
windowing	B-Application
system	I-Application
would	O
then	O
use	O
a	O
series	O
of	O
bit	B-Algorithm
blits	I-Algorithm
using	O
the	O
system	O
's	O
hardware	O
blitter	B-General_Concept
to	O
build	O
a	O
composite	O
of	O
these	O
applications	O
 '	O
bitmaps	O
,	O
along	O
with	O
buttons	O
and	O
sliders	O
,	O
in	O
display	O
memory	O
,	O
without	O
requiring	O
these	O
applications	O
to	O
redraw	O
any	O
of	O
their	O
bitmaps	O
.	O
</s>
<s>
Intuition	B-Application
also	O
anticipated	O
the	O
choices	O
of	O
the	O
user	O
by	O
recognizing	O
the	O
position	O
of	O
the	O
pointer	O
floating	O
over	O
other	O
elements	O
of	O
the	O
screen	O
(	O
title	O
bars	O
of	O
windows	O
,	O
their	O
close	O
and	O
resizing	O
gadgets	O
,	O
whole	O
icons	B-Device
)	O
,	O
and	O
thus	O
it	O
was	O
capable	O
of	O
granting	O
nearly	O
a	O
zero-wait	O
state	O
experience	O
to	O
the	O
use	O
of	O
the	O
Workbench	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
Noteworthy	O
to	O
mention	O
is	O
the	O
fact	O
that	O
Workbench	O
was	O
the	O
only	O
window	B-Application
manager	I-Application
that	O
eventually	O
inspired	O
an	O
entire	O
family	O
of	O
descendant	O
and	O
successors	O
:	O
Ambient	B-Language
in	O
MorphOS	B-Operating_System
,	O
Zune/Wanderer	O
in	O
AROS	B-Application
,	O
Workbench	O
NG	O
(	O
New	O
Generation	O
in	O
AmigaOS	B-Application
4.0	O
and	O
4.1	O
)	O
.	O
</s>
<s>
Workbench	O
4.1	O
was	O
enhanced	O
by	O
2D	O
vector	O
interface	O
powered	O
by	O
Cairo	B-Language
libraries	O
,	O
and	O
presenting	O
a	O
modern	O
Porter-Duff	B-Algorithm
3D	O
based	O
Compositing	O
Engine	O
.	O
</s>
<s>
In	O
1988	O
,	O
Presentation	B-Device
Manager	I-Device
became	O
the	O
default	O
shell	B-Operating_System
in	O
OS/2	B-Application
,	O
which	O
,	O
in	O
its	O
first	O
version	O
,	O
only	O
used	O
a	O
command	B-Application
line	I-Application
interface	I-Application
(	O
CLI	O
)	O
.	O
</s>
<s>
IBM	O
and	O
Microsoft	O
designed	O
OS/2	B-Application
as	O
a	O
successor	O
to	O
DOS	O
and	O
Windows	O
for	O
DOS	O
.	O
</s>
<s>
After	O
that	O
,	O
the	O
Microsoft	O
project	O
for	O
a	O
future	O
OS/2	B-Application
version	O
3	O
became	O
Windows	B-Device
NT	I-Device
,	O
and	O
IBM	O
made	O
a	O
complete	O
redesign	O
of	O
the	O
shell	B-Operating_System
of	O
OS/2	B-Application
,	O
substituting	O
the	O
Presentation	B-Device
Manager	I-Device
of	O
OS/2	B-Application
1.x	O
for	O
the	O
object-oriented	B-Application
Workplace	B-Device
Shell	I-Device
that	O
made	O
its	O
debut	O
in	O
OS/2	B-Application
2.0	O
.	O
</s>
<s>
On	O
systems	O
using	O
the	O
X	B-Operating_System
window	I-Operating_System
system	I-Operating_System
,	O
there	O
is	O
a	O
clear	O
distinction	O
between	O
the	O
window	B-Application
manager	I-Application
and	O
the	O
windowing	B-Application
system	I-Application
.	O
</s>
<s>
Strictly	O
speaking	O
,	O
an	O
X	B-Application
window	I-Application
manager	I-Application
does	O
not	O
directly	O
interact	O
with	O
video	O
hardware	O
,	O
mice	O
,	O
or	O
keyboards	O
–	O
that	O
is	O
the	O
responsibility	O
of	O
the	O
display	O
server	O
.	O
</s>
<s>
Users	O
of	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
have	O
the	O
ability	O
to	O
easily	O
use	O
many	O
different	O
window	B-Application
managers	I-Application
–	O
Metacity	B-Language
,	O
used	O
in	O
GNOME	O
2	O
,	O
and	O
KWin	B-Language
,	O
used	O
in	O
KDE	B-Language
Plasma	I-Language
Workspaces	I-Language
,	O
and	O
many	O
others	O
.	O
</s>
<s>
Since	O
many	O
window	B-Application
managers	I-Application
are	O
modular	B-Architecture
,	O
people	O
can	O
use	O
others	O
,	O
such	O
as	O
Compiz	B-Language
(	O
a	O
3D	O
compositing	B-Operating_System
window	I-Operating_System
manager	I-Operating_System
)	O
,	O
which	O
replaces	O
the	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
Sawfish	B-Language
and	O
awesome	B-Language
on	O
the	O
other	O
hand	O
are	O
extensible	B-Architecture
window	B-Application
managers	I-Application
offering	O
exacting	O
window	O
control	O
.	O
</s>
<s>
Components	O
of	O
different	O
window	B-Application
managers	I-Application
can	O
even	O
be	O
mixed	O
and	O
matched	O
;	O
for	O
example	O
,	O
the	O
window	O
decorations	O
from	O
KWin	B-Language
can	O
be	O
used	O
with	O
the	O
desktop	B-Application
and	O
dock	O
components	O
of	O
GNOME	O
.	O
</s>
<s>
X	B-Application
window	I-Application
managers	I-Application
also	O
have	O
the	O
ability	O
to	O
re-parent	B-Device
applications	O
,	O
meaning	O
that	O
,	O
while	O
initially	O
all	O
applications	O
are	O
adopted	O
by	O
the	O
root	B-Device
window	I-Device
(	O
essentially	O
the	O
whole	O
screen	O
)	O
,	O
an	O
application	O
started	O
within	O
the	O
root	B-Device
window	I-Device
can	O
be	O
adopted	O
by	O
(	O
i.e.	O
,	O
put	O
inside	O
of	O
)	O
another	O
window	O
.	O
</s>
<s>
Window	B-Application
managers	I-Application
under	O
the	O
X	B-Operating_System
window	I-Operating_System
system	I-Operating_System
adopt	O
applications	O
from	O
the	O
root	B-Device
window	I-Device
and	O
re-parent	B-Device
them	O
to	O
window	O
decorations	O
(	O
for	O
example	O
,	O
adding	O
a	O
title	O
bar	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
flash	B-Operating_System
player	I-Operating_System
application	O
can	O
be	O
re-parented	O
to	O
a	O
browser	O
window	O
,	O
and	O
can	O
appear	O
to	O
the	O
user	O
as	O
supposedly	O
being	O
part	O
of	O
that	O
program	O
.	O
</s>
<s>
Re-parenting	B-Device
window	I-Device
managers	I-Device
can	O
therefore	O
arrange	O
one	O
or	O
more	O
programs	O
into	O
the	O
same	O
window	O
,	O
and	O
can	O
easily	O
combine	O
tiling	O
and	O
stacking	B-Device
in	O
various	O
ways	O
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
has	O
provided	O
an	O
integrated	O
stacking	B-Device
window	I-Device
manager	I-Device
since	O
Windows	B-Application
2.0	I-Application
;	O
Windows	B-Application
Vista	I-Application
introduced	O
the	O
compositing	O
Desktop	B-Application
Window	B-Application
Manager	I-Application
(	O
dwm.exe	O
)	O
as	O
an	O
optional	O
hardware-accelerated	O
alternative	O
.	O
</s>
<s>
In	O
Windows	O
,	O
since	O
GDI	B-Operating_System
is	O
part	O
of	O
the	O
kernel	O
,	O
the	O
role	O
of	O
the	O
window	B-Application
manager	I-Application
is	O
tightly	O
coupled	O
with	O
the	O
kernel	O
's	O
graphical	O
subsystems	O
and	O
is	O
largely	O
non-replaceable	O
,	O
although	O
third-party	O
utilities	O
can	O
be	O
used	O
to	O
simulate	O
a	O
Tiling	O
window	B-Application
manager	I-Application
on	O
top	O
of	O
such	O
systems	O
.	O
</s>
<s>
Since	O
Windows	B-Application
8	I-Application
,	O
the	O
Direct3D-based	O
Desktop	B-Application
Window	B-Application
Manager	I-Application
can	O
no	O
longer	O
be	O
disabled	O
.	O
</s>
<s>
Windows	B-Protocol
Explorer	I-Protocol
(	O
explorer.exe	B-Protocol
)	O
is	O
used	O
by	O
default	O
as	O
the	O
shell	B-Operating_System
in	O
modern	O
Windows	O
systems	O
to	O
provide	O
a	O
taskbar	O
and	O
file	O
manager	O
,	O
along	O
with	O
many	O
functions	O
of	O
a	O
window	B-Application
manager	I-Application
;	O
aspects	O
of	O
Windows	O
can	O
be	O
modified	O
through	O
the	O
provided	O
configuration	O
utilities	O
,	O
modifying	O
the	O
Windows	B-Protocol
Registry	I-Protocol
or	O
with	O
3rd	O
party	O
tools	O
,	O
such	O
as	O
WindowBlinds	B-Application
or	O
Resource	B-Application
Hacker	I-Application
.	O
</s>
<s>
The	O
Windows	O
window	B-Application
manager	I-Application
can	O
also	O
act	O
as	O
an	O
X	B-Application
window	I-Application
manager	I-Application
through	O
Cygwin/X	B-Application
in	O
multiwindow	O
mode	O
(	O
and	O
,	O
possibly	O
,	O
other	O
X	B-Operating_System
window	I-Operating_System
implementations	O
)	O
.	O
</s>
<s>
Note	O
that	O
Microsoft	O
and	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
use	O
different	O
terms	O
to	O
describe	O
similar	O
concepts	O
.	O
</s>
<s>
For	O
example	O
,	O
there	O
is	O
rarely	O
any	O
mention	O
of	O
the	O
term	O
window	B-Application
manager	I-Application
by	O
Microsoft	O
because	O
it	O
is	O
integrated	O
and	O
non-replaceable	O
,	O
and	O
distinct	O
from	O
the	O
shell	B-Operating_System
.	O
</s>
<s>
The	O
Windows	B-Application
Shell	I-Application
is	O
analogous	O
to	O
the	O
desktop	B-Application
environment	O
concept	O
in	O
other	O
graphical	B-Application
user	I-Application
interface	I-Application
systems	O
.	O
</s>
<s>
Since	O
2021	O
ChromeOS	B-Operating_System
is	O
shipped	O
with	O
its	O
own	O
window	B-Application
manager	I-Application
called	O
Ash	O
.	O
</s>
<s>
Chromium	O
and	O
ash	O
share	O
common	O
codebase	B-General_Concept
.	O
</s>
<s>
Window	B-Application
managers	I-Application
are	O
often	O
divided	O
into	O
three	O
or	O
more	O
classes	O
,	O
which	O
describe	O
how	O
windows	O
are	O
drawn	O
and	O
updated	O
.	O
</s>
<s>
Compositing	B-Operating_System
window	I-Operating_System
managers	I-Operating_System
let	O
all	O
windows	O
be	O
created	O
and	O
drawn	O
separately	O
and	O
then	O
put	O
together	O
and	O
displayed	O
in	O
various	O
2D	O
and	O
3D	O
environments	O
.	O
</s>
<s>
The	O
most	O
advanced	O
compositing	B-Operating_System
window	I-Operating_System
managers	I-Operating_System
allow	O
for	O
a	O
great	O
deal	O
of	O
variety	O
in	O
interface	O
look	O
and	O
feel	O
,	O
and	O
for	O
the	O
presence	O
of	O
advanced	O
2D	O
and	O
3D	O
visual	O
effects	O
.	O
</s>
<s>
All	O
window	B-Application
managers	I-Application
that	O
have	O
overlapping	O
windows	O
and	O
are	O
not	O
compositing	B-Operating_System
window	I-Operating_System
managers	I-Operating_System
are	O
stacking	B-Device
window	I-Device
managers	I-Device
,	O
although	O
it	O
is	O
possible	O
that	O
not	O
all	O
use	O
the	O
same	O
methods	O
.	O
</s>
<s>
Stacking	B-Device
window	I-Device
managers	I-Device
allow	O
windows	O
to	O
overlap	O
by	O
drawing	O
background	O
windows	O
first	O
,	O
which	O
is	O
referred	O
to	O
as	O
the	O
painter	B-Algorithm
's	I-Algorithm
algorithm	I-Algorithm
.	O
</s>
<s>
Tiling	O
window	B-Application
managers	I-Application
paint	O
all	O
windows	O
on-screen	O
by	O
placing	O
them	O
side	O
by	O
side	O
or	O
above	O
and	O
below	O
each	O
other	O
,	O
so	O
that	O
no	O
window	O
ever	O
covers	O
another	O
.	O
</s>
<s>
Microsoft	B-Application
Windows	I-Application
1.0	O
used	O
tiling	O
,	O
and	O
a	O
variety	O
of	O
tiling	O
window	B-Application
managers	I-Application
for	O
X	B-Operating_System
are	O
available	O
,	O
such	O
as	O
i3	B-Language
,	O
awesome	B-Language
,	O
and	O
dwm	B-Language
.	O
</s>
<s>
Dynamic	O
window	B-Application
managers	I-Application
can	O
dynamically	O
switch	O
between	O
tiling	O
or	O
floating	O
window	O
layout	O
.	O
</s>
<s>
A	O
variety	O
of	O
dynamic	O
window	B-Application
managers	I-Application
for	O
X	B-Operating_System
are	O
available	O
.	O
</s>
<s>
A	O
border	O
is	O
a	O
window	O
decoration	O
component	O
provided	O
by	O
some	O
window	B-Application
managers	I-Application
,	O
that	O
appears	O
around	O
the	O
active	O
window	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
may	O
also	O
display	O
a	O
border	O
around	O
background	O
windows	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
context	O
menu	O
that	O
appears	O
when	O
an	O
alternative	O
click	O
event	O
is	O
applied	O
to	O
a	O
desktop	B-Application
component	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
desktop	B-Application
wallpaper	O
facility	O
that	O
displays	O
a	O
background	O
picture	O
in	O
the	O
root	B-Device
window	I-Device
.	O
</s>
<s>
Focus	B-Application
stealing	I-Application
is	O
a	O
facility	O
some	O
window	B-Application
managers	I-Application
provide	O
.	O
</s>
<s>
It	O
allows	O
an	O
application	O
not	O
in	O
focus	B-Application
to	O
suddenly	O
gain	O
focus	B-Application
and	O
steal	O
user	O
input	O
intended	O
for	O
the	O
previously	O
focused	O
application	O
.	O
</s>
<s>
An	O
iconification	O
facility	O
lets	O
users	O
minimize	O
running	O
applications	O
to	O
a	O
desktop	B-Application
icon	B-Device
or	O
taskpanel	O
icon	B-Device
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
joined	O
windows	O
facility	O
that	O
lets	O
user	O
join	O
application	O
window	O
frames	O
together	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
keyboard	O
equivalents	O
that	O
enables	O
the	O
keyboard	O
to	O
replicate	O
mouse	B-Device
functionality	O
.	O
</s>
<s>
A	O
menu	O
panel	O
a	O
component	O
of	O
some	O
window	B-Application
managers	I-Application
that	O
provides	O
the	O
facility	O
to	O
launch	O
programs	O
using	O
a	O
menu	O
.	O
</s>
<s>
The	O
mouse	B-Application
focus	I-Application
model	O
determines	O
how	O
the	O
pointing	B-Device
device	I-Device
affects	O
the	O
input	O
focus	B-Application
within	O
the	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
The	O
focus	B-Application
model	O
determine	O
which	O
component	O
of	O
the	O
graphical	B-Application
user	I-Application
interface	I-Application
is	O
currently	O
selected	O
to	O
receive	O
input	O
as	O
the	O
pointer	O
is	O
moved	O
around	O
the	O
screen	O
.	O
</s>
<s>
Mouse	B-General_Concept
warping	I-General_Concept
is	O
a	O
facility	O
that	O
centres	O
the	O
pointer	O
on	O
the	O
current	O
application	O
as	O
it	O
is	O
made	O
active	O
.	O
</s>
<s>
A	O
window	B-Application
manager	I-Application
may	O
provide	O
a	O
multiple	B-Application
desktops	I-Application
facility	O
.	O
</s>
<s>
This	O
enables	O
switching	O
between	O
several	O
root	B-Device
window	I-Device
desktops	O
.	O
</s>
<s>
This	O
prevents	O
clutter	O
of	O
the	O
root	B-Device
window	I-Device
,	O
because	O
applications	O
can	O
run	O
on	O
different	O
desktops	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
pager	B-Application
tool	O
that	O
provides	O
the	O
facility	O
to	O
switch	O
between	O
multiple	B-Application
desktops	I-Application
.	O
</s>
<s>
The	O
pager	B-Application
may	O
appear	O
as	O
an	O
onscreen	O
window	O
or	O
as	O
a	O
gadget	O
in	O
the	O
taskbar	O
or	O
taskpanel	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
have	O
a	O
modular	B-Architecture
construction	O
that	O
enables	O
plug-in	O
modules	B-Architecture
to	O
provide	O
features	O
as	O
required	O
.	O
</s>
<s>
A	O
rollup	O
facility	O
enables	O
windows	O
to	O
appear	O
as	O
just	O
a	O
titlebar	O
on	O
the	O
desktop	B-Application
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
root	O
menu	O
,	O
which	O
appears	O
when	O
the	O
root	B-Device
window	I-Device
or	O
desktop	B-Application
background	O
is	O
touched	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
shortcut	O
facility	O
that	O
lets	O
users	O
place	O
icons	B-Device
on	O
the	O
root	B-Device
window	I-Device
that	O
access	O
specific	O
programs	O
or	O
facilities	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
tabbed	O
windows	O
facility	O
that	O
groups	O
applications	O
together	O
in	O
common	O
frames	O
.	O
</s>
<s>
The	O
window	B-Application
manager	I-Application
may	O
provide	O
various	O
task	O
switching	O
facilities	O
that	O
let	O
the	O
user	O
change	O
the	O
currently	O
focused	O
application	O
,	O
including	O
:	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
provide	O
a	O
taskbar	O
that	O
shows	O
running	O
applications	O
.	O
</s>
<s>
The	O
taskbar	O
may	O
show	O
all	O
applications	O
that	O
are	O
running	O
including	O
those	O
that	O
have	O
been	O
minimized	O
,	O
and	O
may	O
provide	O
the	O
facility	O
to	O
switch	O
focus	B-Application
between	O
them	O
.	O
</s>
<s>
The	O
taskbar	O
may	O
be	O
incorporated	O
into	O
a	O
menubar	O
on	O
some	O
window	B-Application
managers	I-Application
.	O
</s>
<s>
A	O
start	O
button	O
is	O
a	O
desktop	B-Application
widget	O
that	O
provides	O
a	O
menu	O
of	O
programs	O
that	O
can	O
be	O
launched	O
.	O
</s>
<s>
A	O
Notification	O
Area	O
is	O
used	O
to	O
display	O
icons	B-Device
for	O
system	O
and	O
program	O
features	O
that	O
have	O
no	O
desktop	B-Application
window	O
.	O
</s>
<s>
It	O
contains	O
mainly	O
icons	B-Device
to	O
indicate	O
status	O
information	O
and	O
notifications	O
such	O
as	O
arrival	O
of	O
a	O
new	O
mail	O
message	O
.	O
</s>
<s>
A	O
titlebar	O
is	O
a	O
window	O
decoration	O
component	O
some	O
window	B-Application
managers	I-Application
provide	O
at	O
the	O
top	O
of	O
each	O
window	O
.	O
</s>
<s>
Title	O
bar	O
buttons	O
are	O
included	O
in	O
the	O
titlebar	O
of	O
some	O
window	B-Application
managers	I-Application
,	O
and	O
provide	O
the	O
facility	O
to	O
minimize	O
,	O
maximize	O
,	O
rollup	O
or	O
close	O
application	O
windows	O
.	O
</s>
<s>
Some	O
window	B-Application
managers	I-Application
may	O
display	O
the	O
titlebar	O
buttons	O
in	O
the	O
taskbar	O
or	O
task	O
panel	O
,	O
rather	O
than	O
in	O
a	O
titlebar	O
.	O
</s>
<s>
An	O
active	O
window	O
is	O
the	O
currently	O
focused	O
window	O
in	O
the	O
current	O
window	B-Application
manager	I-Application
.	O
</s>
<s>
Different	O
window	B-Application
managers	I-Application
indicate	O
the	O
currently-active	O
window	O
in	O
different	O
ways	O
and	O
allow	O
the	O
user	O
to	O
switch	O
between	O
windows	O
in	O
different	O
ways	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
Microsoft	B-Application
Windows	I-Application
,	O
if	O
both	O
Notepad	B-Application
and	O
Microsoft	B-Application
Paint	I-Application
are	O
open	O
,	O
clicking	O
in	O
the	O
Notepad	B-Application
window	O
will	O
cause	O
that	O
window	O
to	O
become	O
active	O
.	O
</s>
<s>
Clicking	O
is	O
not	O
the	O
only	O
way	O
of	O
selecting	O
an	O
active	O
window	O
,	O
however	O
:	O
some	O
window	B-Application
managers	I-Application
(	O
such	O
as	O
FVWM	B-Device
)	O
make	O
the	O
window	O
under	O
the	O
mouse	B-Device
pointer	O
active	O
—	O
simply	O
moving	O
the	O
mouse	B-Device
is	O
sufficient	O
to	O
switch	O
windows	O
;	O
a	O
click	O
is	O
not	O
needed	O
.	O
</s>
<s>
Window	B-Application
managers	I-Application
often	O
provide	O
a	O
way	O
to	O
select	O
the	O
active	O
window	O
using	O
the	O
keyboard	O
as	O
an	O
alternative	O
to	O
the	O
mouse	B-Device
.	O
</s>
<s>
One	O
typical	O
key	O
combination	O
is	O
Alt+Tab	O
,	O
used	O
by	O
Windows	O
and	O
KDE	B-Application
(	O
by	O
default	O
,	O
though	O
this	O
is	O
user-configurable	O
)	O
;	O
another	O
is	O
apple	O
key-tilde	O
,	O
used	O
by	O
Macintosh	O
.	O
</s>
<s>
Many	O
,	O
though	O
not	O
all	O
,	O
window	B-Application
managers	I-Application
provide	O
a	O
region	O
of	O
the	O
screen	O
containing	O
some	O
kind	O
of	O
visual	O
control	O
(	O
often	O
a	O
button	O
)	O
for	O
each	O
window	O
on	O
the	O
screen	O
.	O
</s>
<s>
Each	O
button	O
typically	O
contains	O
the	O
title	O
of	O
the	O
window	O
and	O
may	O
also	O
contain	O
an	O
icon	B-Device
.	O
</s>
<s>
In	O
Microsoft	B-Application
Windows	I-Application
,	O
this	O
area	O
of	O
the	O
screen	O
is	O
called	O
the	O
taskbar	O
;	O
in	O
Apple	O
Macintosh	B-Application
systems	I-Application
this	O
area	O
of	O
the	O
screen	O
is	O
called	O
the	O
dock	O
.	O
</s>
<s>
under	O
the	O
mouse	B-Device
cursor	O
but	O
does	O
not	O
change	O
its	O
Z-order	B-Algorithm
(	O
the	O
order	O
in	O
which	O
windows	O
appear	O
,	O
measured	O
from	O
background	O
to	O
foreground	O
)	O
.	O
</s>
<s>
There	O
are	O
also	O
situations	O
in	O
click-to-focus	B-Application
window	B-Application
managers	I-Application
such	O
as	O
Microsoft	B-Application
Windows	I-Application
where	O
the	O
active	O
window	O
may	O
be	O
obscured	O
;	O
however	O
,	O
this	O
is	O
much	O
less	O
common	O
.	O
</s>
