I wasn't very clear about the expanding the green line. I will try again. In the preview window your file is shown in its entirity. If it is a file bigger than a few minutes it is hard to scroll through the preview to see what you want to keep for the timeline. There is a + and - radio key next to the duplicate button on the lower right of the pane. Hitting the + key moves the green bar smaller and smaller until you get where you can scroll easily through the preview. In version 2.4 the preview does not dissappear when you send the clip to the timeline with the green arrow and you can continue editing with the preview zoomed into the easy to scroll condition. With 3.02 the preview goes away and you need to select the file again but the preview bar is fully expanded. You need to keep hitting the + key to get it back to a usable level. That is time consuming and a real pain. Am I doing something wrong?
Sorry for the long explanation but I don't know all the terms to make myself clear.