Fix GUI issues with KDE Plasma dark theme

mkdir ~/.config-pt
cd ~/.config
cp -rf dconf gtk-3.0 gtk-4.0 xsettingsd ~/.config-pt

  1. Right-click on Menu button.
  2. Click Edit Applications.
  3. Select Packet Tracer.
  4. Add XDG_CONFIG_HOME=/home/jas/.config-pt to Environment variables.
  5. Save.