There seems to be about 20 threads talking about issues with the edting on the timeline, deleting clips etc....
Thought I would share I download and tested Build 12 (as per title) and these issues seem to have been corrected.
I have tested all the issues I had, and they all were restored. If you can confirm your issues were resolved and post here (or if somethign remains broken). keepign it all in one place may help others more quickly.