I haven't encountered this myself with C3, but, assuming this is not an unknown bug in C3, and assuming you're on Windows, I've seen this sort of effect happen on other software when available RAM is low.
If you do not have much available RAM, then depending on the size of your project, you might find it starts closing randomly due to running out of RAM.
Windows doesn't always warn you about this in my experience too, sometimes it will silently close applications (This has happened to me on different computers too, not just my own!)
I checked the RAM usage on my small 400 event project:
RAM when I have C3 open with no project loaded.
RAM when I have C3 open with my project, with the Event List Viewer open.
This increases my RAM usage by a small 50MB.
However, if your project had for instance 2000 or more events, all expanded, then this might be higher. (NOTE: I am assuming that events would up the usage, it could also be amount of sprites, image size of sprites etc.)
It may be worth checking:
- How much RAM do you have?
- How many events does your project have?
- If you work on multiple projects, does C3 crash when you work on a project that is more smaller/less events?
- How much RAM does C3 use when you open it without opening your project?
- If you open C3 and open your project, how heavy is your RAM usage now?
- After using C3 for about 20 minutes of heavy usage, how does your RAM usage look?
Hope this helps!