Thank you, a picture tells a good story
I can confirm that I have/had exactly the same settings for Smooth Tasks Settings, but I am not sure I recognised the importance of the item you point to. This makes me think that I ought to have seen my running apps when the item is not ticked. The system is just a simple MiniMe that I use for testing Shotwell so I am quite happy to delete it if I have got it too mangled. I feel however that replacing the .kde4 with the original for this system I may have recovered.
I understand how you use the spacers, from the looks of it you did not succeed finding a colour or where to change the spacer colour? I seem to remember long ago now that you did look for that very early in kde4 life?
As an experiment I have set a spacer 4 times wider than the one you show. Will see how I feel about that apart from it is wasted space. Since I am such an Opera fan I basically use Opera icon in the panel as a 'marker' between custom icons and running apps icons, the confusion arises when Opera panel Icon is next to the opera apps icon and when I want to open a new instance of Opera I click the wrong one.
I have 8 dt's on the pager, Dolphin, root Konq, user Konq, Kate, Kwrite, Konsole and Opera, Opera 'marks the end' a colourful spacer would then be very nice
I still have not settled for the sequence order apart from Opera sitting at the end of the line.