Hello Zivan, are you using straight cables (DP-DP, DVI-DVI) or adapters?
Is the monitor model properly identified in Device Manager? If not, you will need to get a monitor driver from LG*.
Can you test again without the docking station?
You may want to contact Lenovo* for additional assistance.
One straight (single link DVI->DVI), one not (DP->HDMI). I'll try to get DP->DP cable, DVI->HDMI and try different combinations.
Yes, monitor is identified properly. Driver from LG installed.
Another cable looks like a solution. I replaced straight DVI cable with DVI->HDMI adapter + HDMI cable and screen OK. Strange, but at least verified that it is not a driver issue. Thanks for help.