iMovie is not putting the orange line on clips I have placed in the timeline. How do I get it to do this?

When you click on your project's name under the Project Media tab, the browser should display the project media with orange lines showing which clips have been placed in the project time line. I that is not happening then perhaps a corrupt preference is causing it. Try opening iMovie while holding down the Option and Command keys and selecting to delete preferences in the box that appears. iMovie will open in a new library. Reopen your old library to get back to your projects. Now see if the issue has been solved.

Also, sometimes issues occur that are confined to just one project. Try creating a new project and see if you get the orange lines.

-- Rich

You are welcome. Glad it worked for you. 😊

— Rich