Problem with panels when using multiple monitors

[Makói Krisztián]

Mainly I use my work laptop with an external display. When I need to go to a meeting, I just unplug the monitor and go.
This is when the panel from the external monitor just gets dropped on my laptop display as an additional panel above my regular panel. That way I have duplicate panels and even when I reattach the external monitor, it just stays on the primary as a duplicate.
This is most unfortunate.

Couldn't it be like Cinnamon's way of handling this?
In Cinnamon, when you unplug the external monitor, the main laptop screen remains as it was, all the windows from the external just get moved to the primary. When you reattach the external monitor, the panel there just gets reinstated and you can carry on as usual.

Could that be implemented to MATE somehow?

Thank you for reading this and I hope this can be fixed somehow.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[APolihron (apolitech)]

Please offer us more like what version of mate interfere and what Ubuntu Mate version

[Makói Krisztián (doktorszike)]

Hello, sure thing.

Release: 16.04.3 LTS (Xenial Xerus) 64-bit
Kernel: Linux 4.10.0-32-generic x86_64
MATE version: MATE 1.12.1

For example on this. But it goes way back.

[adam (k-adam-o)]

I tested the panel configuration in Xubuntu and found an option to assign the panel to a fixed screen (like 0/1/2). If the screen is not connected the panel is hidden. Is it posible to make this feature configurable?

[Norbert (nrbrtx)]

Can you reproduce this bug with newer version of Ubuntu MATE?

[Makói Krisztián (doktorszike)]

I will check later today and get back with my findings.

[Makói Krisztián (doktorszike)]

Yes, the issue is still there.
How to reproduce it:
You need to start adding panels to your laptop screen. After all four sides are filled, the next panel will be added to the external monitor. Then you just remove the unnecessary panels from the primary (laptop) monitor, leaving you with what you need on the primary and secondary display.
After you remove the secondary display (external monitor), the panels from there will be added to the primary (laptop) screen.
This is not good, or definitely should not be this way.

After reconnecting the external monitor, at least now the panels are put back to it again, so they don't remain on the primary (laptop) monitor, but transferred back to the secondary (external) display.
That's what changed since.

The original issue is still there though, which is transferring the panels from the secondary screen to the primary screen upon disconnection.

Ubuntu 20.04.2 LTS x86_64 (Ubuntu MATE)
5.4.0-80-generic
MATE 1.24.0
Metacity (Marco)