android - show menu button on galaxy nexus

Question

i need to have the menu button shown for some activities on galaxy nexus . i can't find how to do that, since it hides it by default . i don't wish to create an action bar since it takes more space that i want to use to other things . when setting the "android:targetSdkVersion" value to lower than 14 , it seems to show the menu button , but otherwise, it hides it . btw, the activity needs to be full screen , with no title/action bars .

it is very weird that this button is not shown by default for so many places (even the launcher) , and on some places it does exist . such a button is a very basic one for so many android devices . google decided that not only that , but instead , the switching button is more important to be shown and it's shown by default (no idea if it's possible to hide it, but i guess not , since home button no longer does anything when long pressed) .

anyway, please help me . i'm quite new on android 4 .