some of default settings can't be restored

Hello, it seems “Reset default setup values” doesn’t work properly. When you click the menu command, there are some options can not be reset to default settings:

Doesn’t work:
Gamma
Render
Misc. - Timestamp
Misc. - Recent Files
Misc. - Auto Back Interval
Misc. - Browser Command
Misc. - Visually Linear Color Selection
Misc. - Restrict Real-Valued Handles to Top Right Quadrant
Misc. - Scale New Imported Images to Fit Canvas
Misc. - Enable experimental features (restart required)

The others work fine.

Tested versions: 0.64.1, development snapshot and git master.