Lubuntu 18.10 Screen black bar at top

Description

I have Lubuntu 18.10 on a Lenovo V110 notebook, dual booting with Win10. On starting Lubuntu, the desktop appears, filling the screen as expected, then several milliseconds later, it shrinks vertically to leave a black bar at the top approx 1cm. wide. Perhaps an unhelpful driver or service being loaded near the completion of the startup sequence?

Please, how do I investigate these startup details?

Booting 18.10 from a live USB displays perfectly, so the issue seems confined to the installation. LXQt setting>Monitor setting>Resolution shows the correct resolution (1366×768) for both live and installed versions (even though the display on the installed version is shrunk). Windows 10 also reports 1366×768 and fills the screen.

The issue is shrinkage – not displacement – the bottom of the display is normal – not truncated.(all lower)

The black bar remains even if I change the resolution (via LXQt settings) to any of the other settings (all lower) offered.
This is a new installation – I’m setting up the machine for someone else – and the problem has been there from the start, so I don’t suspect any post-installation changes..

The mouse pointer and Right (not left) button are active on the black bar, but icons dragged onto it disappear as if going behind a curtain.

I’ve explored the wallpaper options (“Stretch to fill screen, Zoom to fill screen” etc with no fix. Also unsuccessfully tried the several other wallpapers offered.

Any clues, please?

Solution

Happened to me too. I fixed it by deleting it: Right click on the top -> Delete panel.