P: Sampling with EyeDropper outside of color palette is not possible with GPU enabled

Lr 6.3 should work also (it does not matter if it is CC or perpetual since it is a bug fix). To make sure that we are talking about the same issue, can you described your specific issue and steps to reproduce it? The specific bug that I mentioned fixed is the case when you try to sample tinting colors for the localized controls (local adjustment brush, linear and circular gradients) via the color palette with the GPU enabled when sampling inside the loupe image.  

It doesn't seem to be working Simon. I tried it on both Mac and Windows, both with latest version and trying GPU on and off...even relaunching LR after changing the setting.

Mine doesn't say LR 6.2 but rather Version 2015.3, Camera Raw 9.3...maybe because I'm a cloud subscriber? It says it's the latest version with no updates available.

Turning off the GPU does not fix the issue on OS X El Capitan using the LR released mid November 2015, 2015.3. It just shows the adjustment brush no matter what button I press.

Editing to add that it also doesn't work when I click in the color picker panel and and drag the cursor over to the photo to pick a color.

Lightroom-6 Color Picker tool will not work to select a color on the image window when GPU is enabled. Only works on the color window, side panels, and monitor desktop.

There are plenty more reasons to turn off GPU Simon. Thanks for the suggestion. In return, maybe you should get back to fixing LR6.... 🙂

Another simpler workaround would be: with the GPU turned on, sample the color from the non-GPU accelerated views such as the navigator view on the top left or detail image render view in the Details panel.

Thanks Victoria, it's true... I just checked and disabling gpu makes this feature/trick work as usual. Still, I hope it is eventually fixed...

(rats! yet another thing spoiled by the gpu acceleration...).

When using the Adjustment brush in LR it used to be that if you left clicked and held down on the color palette you could drag the eye dropper to your photo and select a color from the photo. Now when you do this, the only colors that can be selected are from the interface, desktop, etc. Everything BUT your photo. If you drag to the photo it defaults the palette to white or the X palette. Not useful or desired.