First Impression & Workarounds
Upon first login, you might be greeted by a blank black screen (Ubuntu), or a prompt message asking to select a default WM (Window manager), or both.
In the case of a blank screen, you’ll note that although the panel isn’t showing it’s still there nonetheless. For instance, try clicking on the left lower corner where you’d usually find the “start-menu” button – the menu will show up!
To bring the panel to forefront press Alt + F2 keys and run the command:
lxqt-panel -r which basically tells the OS to replace it.
In order to make the panel show permanently, click the start button and go into: Preferences > LXQt System Settings > Session Settings > select Autostart from the left pane > press Add button > press Search button > choose lxqt-panel > name it LXQt-Panel > click OK.
About the ugly background, whether it’s black, green or whatever, simply choose a different background as you would normally from the system / desktop appearance settings.
Lastly, regarding the prompt for selecting a WM, click on the Search button > and choose mutter / kwin / compiz / etc… if you already have one of them.
Note: by default LXQt opt for Openbox, though if it’s not available you’ll see that message prompting you to select a WM, thus you might want to install Openbox and then choose it as default.
Tip: The reason why LXQt background wasn’t recognized initially is because it’s looking for it inside /usr/share/lxqt-qt5 but there isn’t one there.
Therefore, I suggest you copy the folders from /usr/share/lxqt into /usr/share/lxqt-qt5 in order to prevent any other compatibility issues you may encounter in the future.