Selecting shadows is fiddly

Blocksy theme customizer is one of the best I have used. Except for one thing. Selecting box shadows is difficult mainly due to the selection bar. Both with mouse and touchscreen.

Selection bar is the same everywhere but, for example on box paddings I notice the problem less since I can also write the desired number in the value box. On shadows I couldn’t and could’t select my desired values.

A simpler approach to use only boxes to imput desired values, although not cool it might work better. Or maybe a -/+ buttons solution.