I’m seeing the type in the side bar looking a bit distorted when selected and in the grey bar.
Notice the difference between the two words.
The font is 11 pt. but the size doesn’t seem to matter.
Also note how the replicant red looks when selected. Not real legible.
Adjustments are coming in the next public beta. Thanks for your patience and understanding.
I’m still seeing this in Beta 3.
Which version of macOS do you use? Is font smoothing (see System Preferences > General) enabled? In that case try disabling it.