Ubuntu – Prevent kubuntu from remembering previous session

KDE plasma desktop: http://userbase.kde.org/Plasma

1) Do you have the plasma widget / plasmoid "Show Desktop" on your panel ?

With it you could add the shortcut

2) K > Applications > Help >Application Manuals > Settings > Menu Editor

ie. with the Dolphin; Menu Editor - Advanced tab: Current shortcut key

is there a way to disable the transparency of the bottom panel?

Earlier: How to change color/transparency of all desktop panels?

Found a really easy solution!
Create a file /etc/pm/sleep.d/70-check-recordings.

In this file check if a recording currently is active. If yes, just return exit 1. That's it. Suspend will be aborted.

My script looks like this, it is based on this at tvheadend.

$ cat /etc/pm/sleep.d/00-check-recordings
#!/bin/bash
#
# this script sets ACPI Wakeup alarm and stops standby if a recording is active
# safe_margin - minutes to start up system before the earliest timer

# bootup system x sec. before timer
safe_margin=60

# modify if different location for tvheadend dvr/log path
cd ~hts/.hts/tvheadend/dvr/log

######################

start_date=0
stop_date=0

current_date=`date +%s`

for i in $( ls ); do
        tmp_start=`cat $i | grep '"start":' | cut -f 2 -d " " | cut -f 1 -d ","`
        tmp_stop=`cat $i | grep '"stop":' | cut -f 2 -d " " | cut -f 1 -d ","`
#       logger "$0: $i from $(date -d @$tmp_start) to $(date -d @$tmp_stop)"

        start_extra=`cat $i | grep '"start_extra":' | cut -f 2 -d " " | cut -f 1 -d ","`
        stop_extra=`cat $i | grep '"stop_extra":' | cut -f 2 -d " " | cut -f 1 -d ","`

        let tmp_start=$tmp_start-$start_extra*60
        let tmp_stop=$tmp_stop+$stop_extra*60
#       logger "$0: $i from $(date -d @$tmp_start) to $(date -d @$tmp_stop)"

        # if recording is active, immediately stop suspend 
        # tmp_stop > now and tmp_start < now 
        if [ $((tmp_stop)) -gt $((current_date)) -a $((tmp_start)) -lt $((current_date)) ]; then
                name=`grep -h -A 1 title $i | grep -v  title | sed 's/.*: "\(.*\)"$/\1/'`
                logger "$0: Currently RECORDING $name. No Suspend until $(date -d @$tmp_stop!)"
                exit 1;
        fi

        # only check future recordings
        # tmp_stop > now and tmp_start > now 
        if [ $((tmp_stop)) -gt $((current_date)) -a $((tmp_start)) -gt $((current_date)) ]; then

                # take lower value (tmp_start or start_date)
                # (start_date = 0) or  (tmp_start < start_date)
                if [ $((start_date)) -eq 0 -o $((tmp_start)) -lt $((start_date)) ]; then
                        start_date=$tmp_start
                        stop_date=$tmp_stop
                        name=`grep -h -A 1 title $i | grep -v  title | sed 's/.*: "\(.*\)"$/\1/'`
                fi
        fi
done

wake_date=$((start_date-safe_margin))

# set up wakeup alarm
if [ $((start_date)) -ne 0 ]; then
        logger "$0: Set Wakealarm for $name to $(date -d @$wake_date)"
        echo 0 > /sys/class/rtc/rtc0/wakealarm
        echo $wake_date > /sys/class/rtc/rtc0/wakealarm
fi

Now set up KDE to handle standby after time-out. If a recording is active, KDE standby is aborted by the above script.

See also this in the MythTV documentation.