linux: wrong positioning messages windows

[gucio321]

Hi there,
(referring to OpenDiablo2/HellSpawner#216)
To Reproduce

• run a following code:

func main() {
        for {
                dialog.Message("%s", "Please select a file").Titl
                time.Sleep(1 * time.Second)
        }
}

• accept first message
• take some action in terminal (click, or press any key)
• the next dialog message won't be displayed on the top.
  over that, it will not be placed in the center of the screen.

Screenshots

System Informations
OS: Fedora Workstation 33
desktop: GNOME Shell 3.38.3