Multi-Select is Done!
The first pass on multi-select is done and in for the latest build. It took me a little longer than I wanted to to get everything finished but the first pass is now done. If you grab the latest build you can now translate/rotate/scale multiple parts by holding down ctrl and clicking multiple parts. I think there's still a few little issues to sort out with undo. I also need to do a little bit more work with the rotation. It currently only rotates in local space but I think how I'd like it to work is that if you have a bunch of objects selected and the world transform mode is selected then everything rotates around the center of the selected objects. I'll sort those items out though as I continue work on the 3d workbench feature.