window-list applet doesn't show the windows moved to Display 1

[florisvdh]

This is a duplicate of https://github.com/linuxmint/cinnamon/issues/11319, but given that it only appeared since Mint 21, IMHO seems worth solving in 21.1, where it still occurs in the beta release.

~/.xsession-errors

To reproduce:

1. • Use Display 2 – typically an external monitor connected to a laptop – as sole display, i.e. Display 1 is inactive.
   • Also, use the window-list applet in a panel.
   • Open multiple windows (no matter what).
2. Now activate Display 1 (laptop screen) in the Display settings window (from Settings), use it as extended desktop, still with Display 2 as the primary display.
3. Move a window from Display 2 to Display 1, if not already the case after previous step.

Observation: the window-list only shows windows that are on Display 2, so the windows on Display 1 are inaccessible there (hence cannot be focused on if they are behind another window, except with Alt+Tab).

Expected: windows from both displays (in the same workspace) should be present in the window-list.

Workaround: restart cinnamon with Ctrl+Alt+Esc, but that is an inconvenience. Such restart is included in the above ~/.xsession-errors.

[mtwebster]

https://github.com/linuxmint/cinnamon/commit/4b2713dac582b85dffa1160f09eee3d2a45e7484

[clefebvre]

Fixed

[florisvdh]

Thank you so much!