In the left hand pane, the icons aren't scaled properly. Especially the current selection one is too small. Not sure about the others, they look smallish too compared to the Device selection which seems the only one properly sized. 

My setup: Linux X11 with QT_SCREEN_SCALE_FACTORS=3

(and scaled back down to 2.5 by gnome - which shouldn't matter for this issue afaict as that one scales the entire surface after Qt rendered texts/icons etc)

Seems to me that the active one (Edit) is at scale factor 1, the others are scale factor 2 and the android device icon is the only one properly scaled to 3x.