Full screen mode not filling entire external LED TV screen

[Einstein]

On 4k LED TV's. The video wall fills the entire screen, but when you select a single camera, and click full screen, it only fills a very small portion, maybe as little as 30% of the entire screen. Works fine and as intended on separate Dell 24" and 27" monitors? I have replicated this on all 4 of our security stations that have the 4K external TV connected via HDMI 1.4 cables. I have searched the forums but cannot find anyone else having this issue. I have checked drivers on all 4 stations. 2 laptops, 2 desktops. All 4 support 4K resolutions. Video cards run the gambit from Intel, ATI, and Nvidia.

This is an important feature that we want to find a fix for. I know the cameras only do 1080p, and have tried to lower the resolutions down on all these stations to 1080p down from 4k, but it did not change the output, still just a small portion of the LED TV. We run over 40 cameras, all other features work well. 

Thank you all in advance. 

[PhilipDAth]

I don't know the answer.  I have a customer using a 4k 16:9 monitor without issue/

What is the native aspect ratio of your 4k screens?  Is it 16:9 or something else?

[Einstein]

Well I found a way around it, but its clunky. When I put an individual camera up, I need to click in the area of the picture. I am then presented with a menu, with a selection of "controls". Once I click that I get the option to then go to full screen. So it works, but takes a couple clicks to get there. Not the end of the world, but not ideal. 

fyi Everything is 16:9, 3840 X 2160. So its not a full 4096. Maybe that is the issue. The TV's are commercial Hisense, model 65U1600. 

Thank You!