2 of 2 improved the title

What is a Hanging Sentence?

I am having trouble understanding one of the comments made by my supervisor on the latest draft of our scientific paper. She commented on the first sentence of the draft (Introduction section), she said that the sentence is hanging.

Here is my sentence:

Crowd tragedies continue to take lives all over the world.

btw. She has highlighted the word continue for some reason.

I really want to get this sentence right for the next draft to keep my supervisor motivated for working on the rest of the paper.

I would appreciate any help for improving the sentence or understanding the term 'hanging sentence'.

PS : I googled the term, but all I could find was some information related to dangling modifier. But I am not sure if my sentence falls into this category.