A screenshot: http://veg.by/z/2017-05-14-14-49-58-dc9da754.png
I think they have to have the same height, and it is better to use smaller paddings, like in the toolbar above the drives bar. Now, when Flat buttons are used, these paddings are too big. When non-flat buttons are used, bottom padding is ok, but top padding is also bigger for one pixel for some reason. It is better to use the same paddings everywhere for consistency.
Different height of flat and non-flat drive buttons bar
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