Histogram and Input and Output comparison

[tomczak]

I was trying to compare the histograms of the input and output of an open transformation. I figured that it's possible to toggle histograms by Shift-clicking on the Amount Slider square when the Preview is set either to Output or Side by Side.

I wonder if it would make sense if the Histogram tool had a toggle Input/Output button or perhaps an option to display two histograms if a transformation is open and the preview is set to Side by Side (in the vein of the new Readout tool).

Another thing that came to mind was that perhaps the histogram could be based on input if the display is set to input and the output otherwise? I'm not sure if it would make sense, but the idea is to intuitively compare the image before and after an adjustment.