The Inspiron 15-7559 HDMI out port is only version 1.4a. You should find another PC with DP out port or mDP out to test on the U2713H DP in port or mDP in port. If done and you do not see the issue, the fault was with the laptop 1.4a HDMI out port.

If there is not another PC to test on, you can try the following settings =
* Press the Menu button to open the OSD (On Screen Display)
* Go to Other Settings
* Choose Factory Reset- Reset All Settings
* Go to Display Settings and verify it is using these settings
Aspect Ratio = Wide 16:10
Sharpness = 50
Uniformity Compensation = Off
Smart Video Enhance = Off
* Go to Color Settings and verify it is using these settings
Input Color Format = RGB
Gamma = PC
Preset Modes = Standard
* Exit the OSD

* If installed, open the DDM (Dell Displays Manager)
* Click the tab Auto Mode
* For every application listed, change them to Standard

I connected the display port with the original mini display cable, but I have the same problem again.

I made the display settings you want. Except 16x10 (16x9)

And than i went to the technical service here. They says that the average cost of the exchange is $ 1000.

I really miss the 2312H quality of Dell :(

The Inspiron 7559 does not have a DP out port or mDP out port? So how are you connecting it to the U2713H using the mDP to DP cable?

We do not repair monitors so I have no idea what they meant. We simply replace them while under the purchased warranty period.

I tried with my other pc (microsoft surface pro) has got mDP.

Unfortunately the guarantee is over in January 2018.

I reduce Contrast from 50 to 42. Now it is not worse than before. But it's still not as good as my old monitor (U2312). Sad for Dell if ghosting is a chronic problem for this monitor.