Can't make changes to iMovie project

Hi,

I was working on a 7mn project when iMovie stopped working.

I can open the project but then I cannot make any changes:
-the sliding bar on the right has disappeared
-the "return to library" button has also disappared

I took a picture to let you see how it looks now

I've already tried to:
-delete the com.apple.iMovie8.plist
-create a new account (imovie works but I cannot open the previous project...)

Thank you for help
g

Attached Images

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