Gfilui

I'm on Ubuntu 18.04. I did a clean install, all is nice and quite stable, but I can't see urgent notifications in fullscreen mode (es. YouTube videos in Google Chrome, movies on MPV, Totem or VLC). I tried using --urgency-critical and -u critical, and I saw they're working in normal use as I have to click on the X button to remove them, but this command doesn't put them on top like in 17.10. I don't understand if it's a Gnome Shell bug or I have to do something new.
It's really annoying because I don't see the battery low notification and my laptop switches off everytime I watch a movie. I have to control myself, not comfortable, really.
Anyone knows a workaround or something?

Yes this is very annoying. For workaround, I use zenity's warning dialog-box. It has the benefit of popping up even over full-screen applications:

zenity --warning --text='Battery Low' --no-wrap

Getting the current battery percentage programmatically via script is very easy, but will require a little bit of research on your part, because of variability among systems and manufacturers. Start from here.

Here is my script setup:

This is batteryLevel.sh :

#!/bin/bash

upower -i /org/freedesktop/UPower/devices/battery_BAT1 | grep percentage | sed -r 's/[^0-9]*([0-9]+).*/1/'

This is batteryStatus.sh :

#!/bin/bash

upower -i /org/freedesktop/UPower/devices/battery_BAT1 | grep state | sed -r 's/.*: +(.*)/1/'

Finally, this is batteryInfoNotify.sh :

#!/bin/bash

upperThreshold=99
lowerThreshold=20

echo upperThreshold=$upperThreshold
echo lowerThreshold=$lowerThreshold

zenity --info --text='Battery level monitoring started...' --no-wrap 2>&1 >/dev/null

while [[ true ]]; do
 status=$(~/Scripts/batteryStatus.sh)
 level=$(~/Scripts/batteryLevel.sh)
 msg="Battery Level now is $level%"

 echo "Battery $level% and $status"

 case $status in
 charging | fully-charged)
 if [[ $level -gt $upperThreshold ]]; then
 echo 'Upper threshold crossed...'
 zenity --warning --text="$msg" --no-wrap --timeout=8 2>&1 >/dev/null
 espeak -v en+m7 -p 60 "$msg"
 fi
 ;;
 discharging)
 if [[ $level -lt $lowerThreshold ]]; then
 echo 'Lower threshold crossed...'
 zenity --warning --text="$msg" --no-wrap --timeout=8 2>&1 >/dev/null
 espeak -v en+m7 -p 60 "$msg"
 fi
 ;;
 *)
 echo unexpected battery status
 ;;
 esac

 sleep 30s
done

All of these are in my ~/Scripts and batteryInfoNotify.sh is called at session startup everytime because I set it up so in GNOME Startup Appications.