Remove border on right and bottom

Help me please.

Sorry to ask this mundane question, but how to I remove the border as shown in the image. I use an external monitor and I swapped to a new one and zoomed in/out to get the sizing right.

Now I have this border that I cannot get rid of regardless of what I seem to do.

I’m having the same issue. Everytime I drag the Airtable window to another monitor it causes the border to appear!?

Once I bought a new computer… it went away!!