[suggestion] Missing cancel button when uploading files in post

[shaks]

When making a post in IPB 3.2.3, at the bottom of the post, i can upload files and attach them to the post itself.
Currently, the max single file size is set to 64MB on my forums. However, while looking for the correct file to upload from my computer, quite often, i make the mistake of selecting another file and then i have to wait until the upload is complete before i am allowed to discard that wrong file. This can be a real problem if i have already typed all the information or am editing a reply, so i cannot just close the window and open a new one, as i would lose all the text and tag edits. In that case, i am forced to wait until the attachment upload is complete. This is very annoying when the file size is big, for example, 60MB. In that case, i could be waiting for 30min or one hour depending on my connection upload speed.

So, please add a small cancel upload button somewhere in the box showing the progress of the file when it is being uploaded. This problem exists for both the basic and advanced uploader.