Gazebo Start-up Shadow Settings (Too dark)

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Hello,

When I start Gazebo, for any worlds, it is too dark. I understood that this is due to the shadow options. After I turn off (uncheck) the shadows from World>Scene , it becomes normal (actually, after some time, when I check the Shadow option, it is wrongly checked again, because the appearance is the same (no shadows)).

Is there a way to set no shadows as default? I have to do it manually, which is not a big deal, but I see that people on the Internet(watching some tutorial videos about ROS) don't have this problem. I have Gazebo 9 & Ubuntu 18.04.

Thanks,