Inform File Inspector

Hello to everyone, here’s my problem:

I clicked too quickly between the find and the source window, and my project is stuck with this message:
"You have opened a ‘temporary’ file
The file you have selected to display in the source pane is a temporary file. In other words, it has been loaded from a location, such as from within a library, that is outside your current project. You will be able to view the contents of this file but not edit them.

You can use the File inspector to switch back to your source file."

Pressing OK does nothing, my source is gone, and I have never heard of this File inspector. I can open another project etc., so Inform didn’t just freeze. What can I do? Thanks for the attention.