Stretch to fit screen?

I am using an old Samsung Galaxy S5 to cast to my TV via a Chromecast. The Taplist app does not fill the screen on my phone when in landscape mode- it has a blank space at the top where notifications would be, even though I am using an app called Hide System Bar (which works well in all other apps). I think the Taplist app isnt stretching correctly even though the landscape resolution is 1920x1080.

Would it be possible to attach a screenshot of what’s happening? I’m sure there’s an issue we can fix here, just not totally sure where it’s coming from… Thanks!