A week ago at LTUE (which is an awesome writers conference, and if you have the chance to do next year, you should) I taught a class called Creating Snazzier Sentences. I posted a sentence as an example - I don't recall the exact sentence, but here's one that is similar in structure:
She walked into the grocery store, her purse dangling from her arm.
My point was that whenever you have an "ing" word (also known as a gerund) in a sentence, you need to be able to do that thing while you're doing the other things in the sentence. (I'm sorry - that was confusing. I shall further explain.) Her purse can dangle from her arm while she walks into the grocery store, so this sentence works. However, if the sentence read, "She walked into the grocery store, putting on her shoes," she can't possibly walk and put on her shoes at the same time, so that would be incorrect.
A gentleman in the class had a question - "dangling" is present tense, and the sentence is past tense, so he wasn't sure how that could work together. We were running out of time and I couldn't give the kind of in-depth answer I wanted to, so I thought I'd take that opportunity here and hope that maybe word would leak back to him. :)
Yes, the sentence is in past tense. But look at when her purse is dangling. It's dangling while the past tense sentence is taking place. It's happening in that sentence's here and now, while the walking is going on. Therefore, the "ing" word is all right to use in this sentence. It shows something that is happening concurrently with our main action.
I hope these explanations make sense ... if you have any questions for me or if you'd like me to check out a sentence for correctness, send it on over to me at firstname.lastname@example.org.