Guten Morgan!
I have here a project in Vegas 3.0, and 2 multitrack video parts. Now I want delete the space in the middle and push those 2 parts together. I don't know how to do this? When I want to delete via right-click I delete the whole track, which I don't want.
Do you mean delete empty space on a track between two other parts? If so, under Options make sure "Ripple Edits" is selected. Double click in the empty space and it should highlight from the end of the previous section to the beginning of the next. Press the Delete key. Everything to the right of this empty space will move left to touch the part to the left.
Just click on the left side track display (where the track motion, track-wide filters, and track title are located) and Delete will be on of the things in the pop-up menu. I usually click in the color bar part of the window. The right click menus are highly context sensitive, but that is really a good thing since there are a lot of contexts.