Why run after my Xcode installation to load the dmg file before you can install?

virtual machine installation environment: Mac OS X Lion 10.7.3, Xcode4.3.3

After installing Xcode, can run, you can also bind the Xcode icon in the Dock.

However, after the restart, Xcode icon becomes a question mark. And only by double-clicking. Dmg installation file to run, how is this going?

We had a similar question, how to solve it?
Reply:
Not met, you put xcode install it, because I can not install it, you do not know how to install the program? After the point is xcode dmg icon onto the application to go inside.
Reply:
Upstairs positive solution, the dmg in xcode.app onto the local application can be. The future will not open dmg files.
Reply:
Could not really installed, so you need dmg.