I’m just starting to use DxO Photolab 3 and am enjoying it very much. I do have a couple of suggestions:
How about a pipette tool for the HSL wheel so that I could click on part of the photo and automatically have that color family selected?
Cntr-D is very nice. It would be good to have something similar that would toggle the before/after of the last change made. (making and un-making the change is relatively cumbersome even with the switches). Under the “Compare” button last action, you could add “Last action” to the list - if selected it would change the function of cntr-D to just the last action.
For adjustment you can turn them on/off in adjustment palette or other adjustment has a switch beside their name as you mention, having a shortcut key won’t really make a difference imo.
As for the features suggested, the pipette for HSL is a high demanded feature which will be implemented - so no use to spend the vote for it. As for the second one @mikerofoto suggested a good way out, + it’s possible to use Ctrl+Z/Crtl+U to compare the last change state.
For the more global change for this comparison, we are preparing something new.