Even though I could not pronounce their name, I have to agree with "ayodejiosokoya" that saving the file, quitting C3 and then re-opening the file seems to cure a lot of problems. Though I admit this solution only works if you are experiencing problems you can recover from.

I have also found that C3 works a lot better all around if I turn off all virus scanning software. I also try to exit as many other programs as I can, even though the system monitor will indicate that there is more than sufficient memory to handle everything.