System Information
Windows 8.1, 64bit
Blender Version
Broken: 2.75 RC2 (c85a85a)
Short description of error
F8 disables all addons found in File > Import and File > Export (only Collada will stay, which isn't written in Python).
Exact steps for others to reproduce the error
Start Blender, hit F8, check File menu. At least IO addons enabled by default should stay that way...