It seems to me as if the insync window was planned as a float-only gui element. However, my tiling window manager (i3) forces it into a bigger shape, leaving white spaces where there could be additional content displayed.
Not just this, but when I make the window to float, the out-of-expected shape remains, without the insync window snapping back to its intended size. This leaves also white spaces, even if you resize the insync window.
Linux x260 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux
Maintainer: Luis Manuel R. Pugoy firstname.lastname@example.org
Some screenshots attached.