The frequency resolution of 256 - default "is 0".

Good luck telling what sound it is in 256 - default. The frequency scale is logarithmic from 27 to 20000. If you drew the scale, you can see that it's an increasing tone, starting at about 260Hz. Exactly, it is 12 second sine chirp from 264Hz to 528Hz at max volume.
And by the way, the spectral leakage stop in 256 - default is 396Hz having a period of 128 on 50688Hz sample rate.
Not only make 4096 default (or 2048, or 1024 if you really want time resolution) but also make logarithmic scale the default. Photosounder even goes as far as showing melodic octaves (semitones if vertically zoomed in, increasing in amount the more zoomed) on the right side. On linear scale, the entire top half is octave or less. Linear only could be useful in low frequencies, where it is much more compact than logarithmic (relative to higher frequencies). Also, linear is not how ears work. I don't see how constant frequency resolution with FFT or equally spaced overtones could give useful information. Ears don't hear overtones equally apart.