[GNOME] Unminimize animation starts from the middle of the screen

[IP Productions]

- Plank 0.11.4.33-fb62 (bug also reproduced in stable Plank from default ubuntu repo)
- Ubuntu 18.04.2
- Gnome Shell 3.28.2

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This bug is erratic and happens in turns, going for several clicks with the right animation and then when it gets botched and starts unminimizing for several clicks with the wrong animation.

I can reproduce this bug with several system windows (Nautilus, Settings, Gnome Tweaks) but not with Firefox, e.g.

I used Plank for a long time in Elementary OS Loki and never seen that behavior. It seems very specific to Gnome.

For comparison, the dash-to-dock extension to use the regular Ubuntu panel as dock does not present this behavior, having a very defined animation start.

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[ Terminal Output ]

[WARN 21:52:33.638292] [Environment:165] XDG_SESSION_CLASS not set in this environment!
[WARN 21:52:33.720201] [Theme:508] Currently selected gtk+ theme 'Ambiance' does not provide a dock theme, fallback to the built-in defaults!
[WARN 21:52:33.870335] [LIBDBUSMENU-GLIB] Unable to get session bus: A operação foi cancelada
[WARN 21:52:33.879342] [LIBDBUSMENU-GLIB] Unable to get session bus: A operação foi cancelada
[WARN 21:52:33.930394] Creating surface took WAY TOO LONG (41ms), enabled downscaling for this cache!