Python IDLE can't be opened by double-clicking .py files in Finder

I can't open .py files in IDLE by double-clicking them in Finder (IDLE is currently set as the default program for opening such files). Nor can I open those files by right-clicking and selecting IDLE.

If IDLE is already open I can open .py files through the File > Open method. Once IDLE is open I can also just double-click .py files and they will open in IDLE. Finally, in the Terminal, I can open .py files just fine by typing idle -e file.py even if IDLE has not yet been opened.

I just can't open IDLE itself by double-clicking on .py files, or by right-clicking on .py files and selecting IDLE.

I'm using OSX 10.8.2 and Python/IDLE 2.7.3. Anyone know how I can fix this?

You can right-click on a python file and select get info. Near the bottom of the get info window is a section that reads Open With. You can select a version of Idle to use. There is a button below that reads change all. If you click this, then all files with .py extension will be opened with idle. Just tested this and it works. Below is an image indicating the relevant points.