In the new LXQt desktop, we can intelligently hide the panel. For that purpose, we’ll just need to patch a new file in a location under the meilix-default-settings metapackage.
Originally the file lies in the lxqt folder of the .config of the OS with the name panel.conf like .config/lxqt/panel.conf but since we have to make changes in the metapackage, we need to patch it here meilix-default-settings/etc/skel/.config/lxqt/panel.conf. Files in etc/skel/ will be put in each users’ new home folder, a folder which does not exist yet when we build the ISO.

panel.conf

1. [panel1]
2. alignment=-1
3. animation-duration=0
4. background-color=@Variant(\0\0\0\x43\0\xff\xff\0\0\0\0\0\0\0\0)
5. background-image=
6. desktop=0
7. font-color=@Variant(\0\0\0\x43\0\xff\xff\0\0\0\0\0\0\0\0)
8. hidable=true
9. iconSize=22
10. lineCount=1
11. lockPanel=false
12. opacity=100
13.panelSize=32
14. plugins=mainmenu, desktopswitch, quicklaunch, taskbar, tray, statusnotifier, mount, volume, clock, showdesktop
15. position=Bottom
16. show-delay=0
17. width=100
18. width-percent=true

In the line number 8 , hidable=true is doing all the jobs. It is the only line which hides the panel by default.

How we find this approach?
Originally LXQt panel is not hidden, they are shown by default. I first try to locate panel.conf file which will carry out the configuration for the panel. I try to find the code responsible for hiding the panel, but I can’t find that. Then I copied the panel.conf in a file and then by GUI I hide the panel and reopen the config file. Then I compare the changes between this file and the old config.panel file in which I found that the new file has a new line hidable=true. We introduced the changes in this PR.

How this approach actually work?
We are using meilix-default-settings metapackage to make the things work. We made an .config file which contains the configuration file. And the .config file is present under skel folder which gets copied under the home folder of the user. Thus ultimately we get a configuration file which will overwrite the original one to get the desired changes.

Other Uses of panel.conf
The file panel.conf could be used to customize all related settings to the LXQT panel, like its alignment, volume bar, quick launch, show desktop, etc.

References:
LXQt panel hiding
Customize LXQt desktop