Histogram at top of the right panel now is resized correctly when panel resized

This was a problem forever and apparently I was the only one who ever complained about it. The histogram window was never refreshed when the right side panel was resized. I had to go into Develop, Tone & Color and click the Auto button twice. Once to toggle the state and again to put it back and then the histogram would recalibrate and repaint correctly inside of it's window.

It has been fixed in 2019.