Under preference setting: 3D view: lowest alpha wont shows on tool shelf/properties

I saw one of tutorials. It happens to show the theme background of tool self and properties on 3D view that has alpha. So, i want to do the same t hing on my Blender. So, I went to the Preference setting: 3D view: Theme Space Setting : Region background: it has alpha volume. So, I changed alpha to lower but tool shelf and properties wont change at all. What happen? help meā€¦:confused:

thanksā€¦

In the User Preferences / System panel you also need to enable the ā€˜Region Overlapā€™ tickbox so they do actually show over your 3d view

it works!! many thanks, Richard marklew!!!