VS 2012, PTVS 2.0 RTM
Changes to the build action property are lost when the solution is closed, if no other project changes were pending.
- Create new python application.
- Add new empty python file, accept default name.
- Save all, close and reopen the solution.
- Press F4 to see the item properties for the new empty python file.
- Change the build action from Compile to Content.
- Close the solution, notice how it doesn't ask you to save changes... it doesn't think there are any. You could try to save before closing the solution, but that doesn't help.
- Reopen the solution, check the properties, the build action is still Compile.
Note: I checked NTVS DevBuild 2012-12-17 and it doesn't have that problem.