Gnome-control-center checks the display modes by
cc_display_config_is_scaled_mode_valid()
...
cc_display_config_dbus_is_scaled_mode_valid()
to exclude unusable low resolutions.
However, it is the current using resolution that going to be tested by
is_scaled_mode_allowed() in is_scale_allowed_by_active_monitors(), if it
is global scaled required or configured as cloning mode originally.
Therefor, it will check current using resolution again and again,
instead of the enumerated one. This leads gnome-control-center building
wrong resolution list on the panel.
This patch replaces the current mode with the enumerated mode to have
the correct resolution to be tested by is_scaled_mode_allowed().
Fixes#903
00081c434c