USB startup disk creator says 100% before creating persistence file

[Erasmosis]

When I first used the startup disk creator I didn't fully understand how it worked.
When the dialogue got to 100% and stayed there for a while, I removed the USB disk.

It was still creating the persistence file. Unfortunately, it killed my disk.

I just wish it would say 99% until it's finished creating the persistence file. That would prevent dumb mistakes like mine.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: usb-creator-gtk 0.2.67ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-27.32-generic 4.2.8-ckt1
Uname: Linux 4.2.0-27-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Feb 10 03:49:27 2016
InstallationDate: Installed on 2016-02-01 (9 days ago)
InstallationMedia:

SourcePackage: usb-creator
UDisksDump: Error: [Errno 2] No such file or directory: 'udisks'
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.