Hey,
By accident I moved a file named Pong.h to a folder where there was a file with the name pong.h (notice the lowercase).
Windows doesn't care about the difference and the file Pong.h overwrote the pong.h file.
I have attached two files. One for the project view where you can see that Codeblocks thinks there are two files (Pong.h and pong.h) and another for the File view where you can see that there is only one file (Pong.h)
I understand this started as a mistake on my part, I should have not moved the Pong.h file to where the pong.h was, but I think we can all agree that there is also an issue with codeblocks in the handling of all this. First for not warning me about the name collision and secondly for "thinking" that there are two files.
I believe on linux the files will seem different but not on windows
Windows 10 pro - Codeblocks 16.01