I finally tried the new align dialog. I realize it's a work in progress but still here are some comments:

- BUG: when I open the align dialog, then switch to another non-Inkscape window and then back to Inkscape, the dialog disappears. Even when I switch focus to the editing window, the dialog disappears (not only sinks but disappears completely). This does not happen with e.g. Fill&Stroke dialog, and it must be fixed as soon as possible.

- merging the two tabs into one makes sense, but then remove the lone "Align" tab

- the new title "Docker" tells me nothing - Align and Distribute is what it does, so that is the title it should use; also don't lose the shortcut listed in the dialog title, as in all other dialogs

- the anchor menu must have an appropriate label, e.g. "Relative to:"

- the anchor meny only applies to alignment, not distribution, and therefore must be inside the Align frame

- the old behavior corresponds to Selection, and therefore Selection must be the first and the default selected item in the anchor menu; it's also the most intuitive

- the Last/First Selected items may be confusing, because in many cases the order or selection is undefined (e.g. when you do a rubberband around several objects), so please remove them and add Top/Bottom Object (referring to z-order) instead

- in the node mode, none of the anchor menu items make sense (nodes have no bigger/smaller, no z-order, etc) so the menu must be removed, instead it should always align within the bounding box of the selected nodes

It looks very promising, so I look forward to your further work on this! :)