Problem with my monitor

i have a problem with my monitor. i buy a new Dell monitor 2 days now and i see in blue colour some thin white lines horizontally. this problem is only in a few colours like blue, green, red. in black colour in grey or yellow for example i dont have problem. the colour is clear and spot.

i use the hdmi cable that is in package with my monitor and in my previus monitor i have dvi cable...i dont know if this is normal or is a monitors problem. i dont have experience in dell monitor before. is my first time that im working in dell monitor with hdmi cable.