Description of problem:
When run as a normal user, unetbootin displays a message requesting to be run as root.

When run as root, unetbootin just displays a gray window. The console shows the following messages:
[alex@karlalex ~]$ su - -c '/usr/bin/unetbootin'
Contraseña: 
X Error: BadAccess (attempt to access private resource denied) 10
  Extension:    130 (MIT-SHM)
  Minor opcode: 1 (X_ShmAttach)
  Resource id:  0x125
X Error: BadShmSeg (invalid shared segment parameter) 128
  Extension:    130 (MIT-SHM)
  Minor opcode: 5 (X_ShmCreatePixmap)
  Resource id:  0x7d
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2000010
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x2000010


Version-Release number of selected component (if applicable):
unetbootin-608-3.fc22.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Attempt to run /usr/bin/unetbootin as root
2.
3.

Actual results:
Blank window and X errors on console

Expected results:
Application widgets should display normally

Additional info:

When run anyway as an ordinary user, unetbootin performs all of the steps for creating the USB stick, except that it *silently* fails to run syslinux on it. The user is left with an unbootable stick with no warning at all.