!!! still the double click problem !!! :? 
May be a workaround to this problem. Seems to be a problem with DDE, as previously.
If you are administrator of your account :
1 ) in Explorer, open Tools/Options/file type (may be not exactly this, because it's a raw translation of my french windows!)
2 ) look at CBP file association
3 ) Normally associated to codeblocks with a "modify" button and at the bottom an "Advanced" button. If at the bottom you have a "Restore" button, click on it to restore standard association and the "Advanced" button.
4 ) Click on the "Advanced" button.
5 ) in actions, choose "open" then click the "Modify..." button.
6 ) uncheck the "use DDE" for this action.
7 ) Close all windows.
8 ) open Codeblocks by double clicking on a .cbp file.
9 ) a window is opened to choose if you want to associate C files with codeblocks. Choose the first proposition "No". Normally, it's already done by your previous installation. (If you click one of the "yes" DDE will be reactivated, and the bug is still alive !!)
10) close and reopen codeblocks by double clicking on your .cbp file. It should work now.
If you are not an administrator the "advanced" button is grayed.
You can try to edit the registry (be carefull !!!!, may be dangerous if you are not sure) with regedit.
Open regedit, find the registry key HKEY_CLASSES_ROOT\CodeBlocks.cbp\shell\open and delete the subkey ddeexec.
Close the registry and start codeblocks by double clicking a .cbp file.
Then go to 9 ).
This is for .cbp association, but you have to do this also manually for the other ones : .c, .cpp, .h,....
I tried this on Windows XP SP2 and Windows 2000 with success.
Gd_on
