If I leave form page for approx 10 minutes – unable to remove files from form

I added 3 images.
They got uploaded to server and show in form as 100% uploaded.
Then I select another tab in browser.
After a little more than 10 minutes I go back to tab with the 3 images in upload form.
If I click remove icon, I see “Removing file”, but nothing is removed in the form…
Reason upload form is not cleaned up, is probably that image has been deleted from the server.

I repeated this, added 3 images. Went to another tab in browser windown and waited a little more than 10 minutes.
Then I checked the upload folder on the server and saw that two of the three images where deleted.
Then I go back to tab with upload form again, and try to delete images. Then I could only remove the image in the form which still had corresponding image on server.

I think that waiting 10 minutes before deleting images is way to short.
Let say a customer start filling out the form, add some images.. and then have to do something else for a while – before finishing the form (sending it) – then I bet that person would be a little annoyed having to reload the form in order to make it work right again.
This should be handled in some way or another.
Why delete any image so fast (in this case) – when default deletion is 1 hour after sending the form (email)?

Please do not delete images before 1 hour, or eventually add a custom delay field in backend to handle situations like this.