peterlewis reported an issue where canceling an image upload would leave the uploading process stuck. This occurred in Discourse 1.8.9 on Safari/Sierra (10.12.6). The user found that canceling the reply and clicking reply again would update the state to “Uploading 0%”, but the issue would persist until the page was reloaded.
peterlewis provided reproduction steps, which involved dragging a large image, waiting for it to start, canceling, and repeating the process. zogstrip suggested that the issue might have been fixed by @gerhard, but gerhard clarified that they had only fixed the issue on mobile.
After further investigation, zogstrip was unable to reproduce the issue on Windows 10/Chrome 63.0.3239.132. peternlewis later confirmed that the issue appeared to be fixed.