[r8500, r8504] Opening of save dialog closes other dialogs

[Emil Sawicki]

I'm playing Simutrans always with some dialogs on the screen: stop list, line management etc. As always, I'm using the "s" hotkey to open game saving dialog and now the other windows disappear like when pressing [Backspace]. Same thing occurs when I open the save dialog via menu. There was no such problem in 120.2.

[Dwachs]

should be fixed in r8506. thanks for reporting