Hi and Welcome!
voon wrote:- The pane coloring ... I'd like it to be as simple as in xplorer2 ... the active pane has a completely gray background ... I don't want it to only color the active column in the pane. How can I achieve that?
I don't know how it is in xplorer2, but here are the relevant places to make changes.
Assuming that you want everything white: go to Tools>Configuration>Colors & Style>List>Sorted column> set it to white. If you want do the same for all modes (Browse, Find etc) in List dropdown menu.
Next, set Inactive pane to also white.
voon wrote:- Path clicking ... can the full, absolute path be made clickable somehow to jump to directories inside the path? I.e. in a path U//V/W/X/Y/Z I'd like to click on W to end up there.
Win7 type breadcrumb has been requested before, not sure if XY will get it, but something similar can be done. Right-click on Address bar's down arrow and you'll see relevant paths for your current folder. Similarly, on the tab right-click on the icon to get relevant paths.
voon wrote:- "back" button on the mouse should bring me back one level in the directory tree.
I am not sure if this is a XY related question, maybe you can configure your mouse back button to backspace?
Also interesting for you maybe simply double-click in list's empty space you will be taken one level up.
Relevant setting is: Tools>Configuration>Extended>Mouse>Double-click on empty space goes up. This is already enabled by default.