Automatically adding to timeline

My version is 15.0.1 Build 73.

When I import a file into After Effects, it automatically adds it to the timeline

and creates a new composition. It never has done this before. Usually, it

imports the file into the left hand panel (not sure of the precise name) and

then I can drag it into either the timeline or the "new composition" icon.

I know that there is a new update but the update doesn't mention fixing

anything like this.  Is this a new feature or do I have to change some settings?

If I am creating one composition with different files, I have to stop and delete

each new composition that it has made and then add the file to my original

composition.

Thanks