Created attachment 64479 [details]
Screenshot of the dispaly settigns output form system tools

Version:           unspecified (using KDE 4.6.5) 
OS:                Linux

I use a laptop and several different external monitors. When using the external monitors I deactivate the laptop screen with a script using xrandr thus :-

H208
"xrandr --newmode "1920x1200R"  154.00  1920 1968 2000 2080  1200 1203 1209 1235 +hsync -vsync
xrandr --addmode VGA1  "1920x1200R"
xrandr --output LVDS1 --off
xrandr --output VGA1 --mode 1920x1200R"

I have several similar scripts for different monitors, external projectors and so on.

The laptop LCD is 1280X800. One monitor is 1366X768, which works fine, but the other is 1920x1200 which is where the problem arises. I have two horizontal panels, one at the top of the screen, and one at the bottom, both of which are set to 'Maximize' (i.e. full screen width). I have previously encountered the bug where I have to resize the panels to get the full width of the 1366X768 monitor - not a big problem for me.
I have no vertical panels.

I used the very large monitor (1920X1200) yesterday for the first time in several months. It had worked fine with KDE 4.3.  I had to manually enlarge the panels, but it worked. I used it yesterday, with the script above, manually extended the panels as usual, and worked away.

Last night I used the laptop alone. The panels run the full width of the screen, and disappear off the right hand side. The control buttons on the panels, which lie at the right end of the panel, are inaccessible. Windows on the screen will not slide past the right hand edge of the screen. I can't get at the control buttons to resize the panel - which is the key problem.

Same problem this morning! - works fine on external monitor, laptop panels still disappear out into space.
Xrandr output
"# xrandr
Screen 0: minimum 320 x 200, current 1280 x 800, maximum 8192 x 8192
LVDS1 connected 1280x800+0+0 (normal left inverted right x axis y axis) 331mm x 207mm
   1280x800       60.0*+
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
TV1 disconnected (normal left inverted right x axis y axis)
  848x480 (0x105)   29.0MHz
        h: width   848 start  849 end  912 total  944 skew    0 clock   30.7KHz
        v: height  480 start  481 end  512 total  513           clock   59.9Hz
  640x480 (0x106)   22.6MHz
        h: width   640 start  641 end  704 total  736 skew    0 clock   30.7KHz
        v: height  480 start  481 end  512 total  513           clock   59.9Hz
  1920x1080 (0x107)  134.5MHz
        h: width  1920 start 1921 end 1984 total 2016 skew    0 clock   66.7KHz
        v: height 1080 start 1081 end 1112 total 1113           clock   59.9Hz
  1280x1024 (0x108)   87.2MHz
        h: width  1280 start 1281 end 1344 total 1376 skew    0 clock   63.4KHz
        v: height 1024 start 1025 end 1056 total 1057           clock   59.9Hz
  1280x720 (0x109)   62.1MHz
        h: width  1280 start 1281 end 1344 total 1376 skew    0 clock   45.1KHz
        v: height  720 start  721 end  752 total  753           clock   59.9Hz
  1024x768 (0x10a)   53.8MHz
        h: width  1024 start 1025 end 1088 total 1120 skew    0 clock   48.0KHz
        v: height  768 start  769 end  800 total  801           clock   59.9Hz
  800x600 (0x10b)   34.0MHz
        h: width   800 start  801 end  864 total  896 skew    0 clock   37.9KHz
        v: height  600 start  601 end  632 total  633           clock   59.9Hz
"
I attach the output of the Display size and orientation system settings as a screenshot.

.kde4/share/config/plasma-destoprc
"
[$Version]                                                                                                                                                                          
update_info=plasma_popupapplet_fix_groups.upd:PlasmaPopupAppletFixGroups2                                                                                                           
                                                                                                                                                                                    
[BackgroundConfigDialog]                                                                                                                                                            
Height 1050=719                                                                                                                                                                     
Height 1200=719                                                                                                                                                                     
Height 800=715                                                                                                                                                                      
Width 1280=807                                                                                                                                                                      
Width 1680=650                                                                                                                                                                      
Width 1920=652                                                                                                                                                                      

[Colors]
CurrentPalette=Forty Colors

[DownloadDialog Settings]
Height 800=400
Width 1280=700

[General]
perVirtualDesktopViews=true

[PlasmaViews][1]
panelVisibility=0

[PlasmaViews][1][Horizontal1280]
offset=0

[PlasmaViews][1][Horizontal1920]
offset=0

[PlasmaViews][1][Sizes]
lastsize=1280

[PlasmaViews][1][Sizes][Horizontal1024]
max=1280,27
min=1280,27
offset=0
size=1024,27

[PlasmaViews][1][Sizes][Horizontal1280]
max=-1,-1
min=-1,-1
offset=0
size=1024,27

[PlasmaViews][1][Sizes][Horizontal1680]
max=-1,-1
min=-1,-1
offset=0
size=1120,700

[PlasmaViews][1][Sizes][Horizontal1920]
max=-1,-1
min=-1,-1
offset=0
size=1024,27

[PlasmaViews][10]
panelVisibility=0

[PlasmaViews][10][Horizontal1280]
offset=0

[PlasmaViews][10][Sizes]
lastsize=1280

[PlasmaViews][10][Sizes][Horizontal1024]
max=-1,-1
min=-1,-1
offset=0
size=1024,26

[PlasmaViews][10][Sizes][Horizontal1280]
max=-1,-1
min=-1,-1
offset=0
size=1024,26

[PlasmaViews][2]
panelVisibility=0

[PlasmaViews][2][Horizontal1280]
offset=0

[PlasmaViews][2][Horizontal1920]
offset=0

[PlasmaViews][2][Sizes]
lastsize=1280

[PlasmaViews][2][Sizes][Horizontal1024]
max=1280,31
min=1280,31
offset=0
size=1024,31

[PlasmaViews][2][Sizes][Horizontal1280]
max=-1,-1
min=-1,-1
offset=0
size=1024,26

[PlasmaViews][2][Sizes][Horizontal1680]
max=-1,-1
min=-1,-1
offset=0
size=853,533

[PlasmaViews][2][Sizes][Horizontal1920]
max=-1,-1
min=-1,-1
offset=0
size=1024,26

[Updates]
performed=/usr/share/apps/plasma-desktop/updates/systray-to-notifications-widget.js

[ViewIds]
3=1
45=3
46=4
47=5
48=6
49=7
50=8
51=2
"

Reproducible: Always

Steps to Reproduce:
Use laptop
Connect to monitor as above
Reuse laptop

Actual Results:  
Panel edges falloff the screen

Expected Results:  
Panel edges go to edge of screen

Possibly related bugs
https://bugs.kde.org/show_bug.cgi?id=247205
https://bugs.kde.org/show_bug.cgi?id=189883

There are quite a few bugs marked as duplicates of one or other of these. The core issue is that KDE perhaps ought to decide what screensize to use based on the screensize of whichever display 1 it is using.  My use case - laptop *or* variable external monitors is, I suspect, far commoner that multiple display setups.

I'm going to try deleting the plasma-desktoprc file, and I will tell you what happens when I restart KDE

All the best, and thanks for all the great work
Anthony Staines