Release 0.1.2 is now out and it supports deleting light strings from the Display Element list. Select one or more strings and either right-click for the context menu or press the "Delete" key. Also, just about everything that can be deleted in Olive Studio can be undone using "undo" at the top of the window.
I inadvertently missed a question by Rick above about additional display element types. More types beyond the light string will be developed eventually. I've made some modifications to the plugin interface for display elements, so once that is stable, I will throw in a few more. Of course, I'm looking forward to releasing the Plugin Development Kits so I'm not the bottleneck for everyone's great ideas.
PixelNet output over comm port is also implemented, but there's a performance issue that I need to address. So if you're fortunate enough to have a Dongle with the PixelNet firmware and some SmartStrings, maybe you could test it out.
Thanks,
--Matt