[chrisrkline]

If you set the project as sequential you will only see action1 in your context view. Action2 will appear when and only when Action1 is completed (this assumes you are viewing Available in the Availability Filter in the View bar--Shift-Command-V.

It is not possible to have action2 actually "start" only when action1 completes. But it will hide itself until action1 is completed in a sequential project.