Comment 2 for bug 1666178

StacktraceTop:
 require () at ./src/include/common/mir/require.h:28
 mir_create_modal_dialog_window_spec (connection=0x55a59cc97960, width=539, height=164, parent=0x0) at ./src/client/mir_surface_api.cpp:108
 mir_connection_create_spec_for_modal_dialog (connection=<optimized out>, width=<optimized out>, height=<optimized out>, format=mir_pixel_format_argb_8888, parent=<optimized out>) at ./src/client/mir_surface_api.cpp:931
 create_window_type_spec (buffer_usage=<optimized out>, type=<optimized out>, modal=<optimized out>, height=<optimized out>, width=<optimized out>, y=0, x=0, parent=0x0, display=0x55a59cc9a040) at ././gdk/mir/gdkmirwindowimpl.c:385
 create_spec (window=window@entry=0x55a59dcdeaf0, impl=impl@entry=0x55a59d6d9e70) at ././gdk/mir/gdkmirwindowimpl.c:431