**System Information**
Arch Linux (x86-64)
nVidia Geforce GTX 670
**Blender Version**
Broken: blender-2.69-d4a1138-linux-glibc211-x86_64
**Short description of error**
The Cycles "Strength" input box in the Background shader node is too sensitive when it is operated by mouse.
**Exact steps for others to reproduce the error**
Select Cycles Render. Go to World in Properties editor. Use Nodes. Drag the value of the Strength input box by mouse.