This is more of a general Solidworks question.
As far as I can tell, these were saved in exactly the same manner. I didn't change the case. Something else changed it.
I have noticed this over the years and never really thought much of it. Today, I ran into it and thought....let's ask.
Below is another example:
Here, in the BOM, when I RMB on the part, it shows up lower case:
In fact, for every part in the BOM the "Open.." spot on the RMB tree is all lower case.
But when I open that part, you can see that it is Upper case in the actual file name and the title at the top of the tree:
When I create a drawing of it, all upper case:
I find this odd, because in order to make it lower case, Solidworks programmers have you have to to specify it to be lower case because it was saved in uppercase. It seems like this was done on purpose, but I don't understand it.
The only reason that I really bring this up is that at one point, we (Rick Becker and I) were having an issue with part templates in which, which seemed to stem from uppercase template extensions vs lowercase template extensions. Jim Wilkinson resolved the issue, but I just wonder......
Why?
SW 2015 Sp5 / Windows 10 64bit.
Windows is not case sensitive in general; meaning you can't actually have files with the same name with just case being different. For instance, you can't have two files in the same folder called file.txt and FILE.txt or file.TXT or FiLe.TxT.
So, case is really just a convenience for users for visualization of the filename in the Window OS. It has varied over the years and releases of MS. I remember in past OS versions when the operating system would change the case of text in a filename without the user trying to do so. I also remember that if you had a file called file.TXT and tried to change it to file.txt, you couldn't do it...you'd have to change it to file1.txt and then file.txt (it didn't see capitalization changes as filename changes so you had to change it to some other name and back to the original name to get the capitalization to change).
Now, some things about SOLIDWORKS and the case sensitivity:
I hope that explains it all,
Jim