My current setup:
Gentoo ~amd64
KDE Apps 15.04.3
KDE Frameworks 5.11.0
KDE Plasma 5 5.3.2
CI7-4770 and CI7-4790
4600 HD
8 GB ram
Virtual desktops = 2x4
Desktop effects>Desktop Grid = Zoom duration = default, Border width = 0, Desktop name alignment = disabled, Layout mode = pager, Use present windows effects to layout the windows = not checked. Trigger = upper left hand corner of screen
Desktop Layout = Folder View, Wallpaper Type = Slideshow, Change every 30 seconds, Folder = /usr/share/wallpapers

Problem:
When I execute the Desktop Grid and the four desktops are displayed, a small rectanglar box, located in the lower right hand section of each desktop, is displayed. This small rectanglar box is of the last desktop and the current information located in that position. As the Folder View slideshow changes, the small rectanglar box will continue to be displayed and not over written. I can select another desktop and select desktop grid again and the last desktop before desktop grid is selected will be the info that is displayed in the small rectanglar box

The photo shows the four virtual desktops using the desktop grid effect. A white arrow is used in the top left desktop to indicate the small rectanglar box issue.
http://imgur.com/MLVpRy6

You may want to paste here (in a code block) KWIn's supporting information by typing this in a terminal:

qdbus org.kde.KWin /KWin supportInformation

qdbus org.kde.KWin /KWin supportInformation

Code: Select all

KWin Support Information:
The following information should be used when requesting support on e.g. http://forum.kde.org.
It provides information about the currently running instance, which options are used,
what OpenGL driver and which effects are running.
Please post the information provided underneath this introductory text to a paste bin service
like http://paste.kde.org instead of pasting into support threads.

==========================

Version
=======
KWin version: 5.3.2
Qt Version: 5.4.2
Qt compile version: 5.4.2
XCB compile version: 1.11

Operation Mode: X11 only

Build Options
=============
KWIN_BUILD_DECORATIONS: yes
KWIN_BUILD_TABBOX: yes
KWIN_BUILD_ACTIVITIES: yes                                                                                                                       
HAVE_WAYLAND: no                                                                                                                                 
HAVE_WAYLAND_EGL: no                                                                                                                             
HAVE_WAYLAND_CURSOR: no                                                                                                                           
HAVE_XKB: no                                                                                                                                     
HAVE_INPUT: no                                                                                                                                   
HAVE_XCB_CURSOR: yes                                                                                                                             
HAVE_XCB_SYNC: yes                                                                                                                               
HAVE_X11_XCB: no                                                                                                                                 
                                                                                                                                                 
X11                                                                                                                                               
===                                                                                                                                               
Vendor: The X.Org Foundation                                                                                                                     
Vendor Release: 11701000                                                                                                                         
Protocol Version/Revision: 11/0                                                                                                                   
SHAPE: yes; Version: 0x11
RANDR: yes; Version: 0x14
DAMAGE: yes; Version: 0x11
Composite: yes; Version: 0x4
RENDER: yes; Version: 0xb
XFIXES: yes; Version: 0x50
SYNC: yes; Version: 0x31
GLX: yes; Version: 0x0

Decoration
==========
Plugin: org.kde.breeze
Theme:
Blur: 0
onAllDesktopsAvailable: true
alphaChannelSupported: true
closeOnDoubleClickOnMenu: false
decorationButtonsLeft: 0, 2
decorationButtonsRight: 6, 3, 4, 5
borderSize: 3
gridUnit: 16
font: DejaVu Sans,11,-1,5,75,0,0,0,0,0
smallSpacing: 4
largeSpacing: 16

Options
=======
focusPolicy: 0
nextFocusPrefersMouse: false
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
shadeHover: false
shadeHoverInterval: 250
separateScreenFocus: false
placement: 4
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
rollOverDesktops: false
focusStealingPreventionLevel: 1
legacyFullscreenSupport: false
operationTitlebarDblClick: 5000
operationMaxButtonLeftClick: 5000
operationMaxButtonMiddleClick: 5015
operationMaxButtonRightClick: 5014
commandActiveTitlebar1: 0
commandActiveTitlebar2: 30
commandActiveTitlebar3: 2
commandInactiveTitlebar1: 4
commandInactiveTitlebar2: 30
commandInactiveTitlebar3: 2
commandWindow1: 7
commandWindow2: 8
commandWindow3: 8
commandWindowWheel: 31
commandAll1: 10
commandAll2: 3
commandAll3: 14
keyCmdAllModKey: 16777251
showGeometryTip: false
condensedTitle: false
electricBorderMaximize: true
electricBorderTiling: false
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
hideUtilityWindowsForInactive: true
inactiveTabsSkipTaskbar: false
autogroupSimilarWindows: false
autogroupInForeground: true
compositingMode: 1
useCompositing: true
compositingInitialized: true
hiddenPreviews: 1
unredirectFullscreen: false
glSmoothScale: 2
colorCorrected: false
xrenderSmoothScale: false
maxFpsInterval: 16666666
refreshRate: 0
vBlankTime: 6000000
glStrictBinding: true
glStrictBindingFollowsDriver: true
glCoreProfile: true
glPreferBufferSwap: 112
glPlatformInterface: 1

Screen Edges
============
desktopSwitching: false
desktopSwitchingMovingClients: false
cursorPushBackDistance: 1x1
timeThreshold: 0
reActivateThreshold: 1050
actionTopLeft: 0
actionTop: 0
actionTopRight: 0
actionRight: 0
actionBottomRight: 2
actionBottom: 0
actionBottomLeft: 0
actionLeft: 0

Screens
=======
Multi-Head: no
Active screen follows mouse:  no
Number of Screens: 1
Screen 0 Geometry: 0,0,1920x1080

Compositing
===========
Compositing is active
Compositing Type: OpenGL
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Haswell Desktop
OpenGL version string: 3.3 (Core Profile) Mesa 10.6.1
OpenGL platform interface: GLX
OpenGL shading language version string: 3.30
Driver: Intel
GPU class: Haswell
OpenGL version: 3.3
GLSL version: 3.30
Mesa version: 10.6.1
X server version: 1.17.1
Linux kernel version: 4.1.1
Direct rendering: Requires strict binding: yes
GLSL shaders:  yes
Texture NPOT support:  yes
Virtual Machine:  no
OpenGL 2 Shaders are used
Painting blocks for vertical retrace:  no

Loaded Effects:
---------------
zoom
slidingpopups
kwin4_effect_login
screenshot
kwin4_effect_windowaperture
minimizeanimation
kwin4_effect_translucency
desktopgrid
kwin4_effect_fade
kwin4_effect_maximize
kwin4_effect_dialogparent
highlightwindow
blur
contrast
logout
dashboard
startupfeedback
kscreen

Currently Active Effects:
-------------------------
blur
contrast

Effect Settings:
----------------
zoom:
zoomFactor: 1.2
mousePointer: 0
mouseTracking: 0
enableFocusTracking: false
followFocus: true
focusDelay: 350
moveFactor: 20
targetZoom: 1

slidingpopups:
fadeInTime: 150
fadeOutTime: 250

kwin4_effect_login:

screenshot:

kwin4_effect_windowaperture:

minimizeanimation:

kwin4_effect_translucency:

desktopgrid:
zoomDuration: 300
border: 0
desktopNameAlignment: 0
layoutMode: 0
customLayoutRows: 2
usePresentWindows: false

kwin4_effect_fade:

kwin4_effect_maximize:

kwin4_effect_dialogparent:

highlightwindow:

blur:
blurRadius: 12
cacheTexture: true

contrast:

logout:
useBlur: true

dashboard:
brightness: 0.5
saturation: 0.5
blur: false

startupfeedback:
type: 0

kscreen:

https://bugs.kde.org/show_bug.cgi?id=348577
https://git.reviewboard.kde.org/r/124136/

This issue has been resolved since further revisions to KDE have occurred. Currently the problem doesn't exist with the following versions:
KDE Apps 15.08.3
KDE Frameworks 5.16.0
KDE Plasma 5 5.4.3