Calc will function fine when first opened. But gradually it will become slower and slower in responding to basic functions - placing a cursor in a cell, making a calculation, especially applying colors to cells with the pulldown menu. Any of these can take 3-5 seconds to engage. If you close and reopen it will again work fine but again gradually degrade. Today I monitored RAM usage of the program which made it clear this is a major memory leak issue. When the program opened it used 258 MB. About 5 hours later the program was using more than 1 GB of memory. Still the program was functioning OK. I do not know what memory usage is when it becomes almost non-functional. This is unacceptable for a program that claims to be an alternative to microsoft's excel. I hope those who do the programming work can address this asap.
I guess you could analyze it with this: https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/InstrumentsUserGuide/index.html#//apple_ref/doc/uid/TP40004652-CH3-SW1
This isn't a valid bug report - there is nothing for us to confirm. Closing as INVALID. as far as working on this ASAP - that's not how open source projects work. Unlike Microsoft (who you and its clients pay a lot of money to), we're a free project that is based on volunteers who work on things *as they please*. We have a strong culture of "the doers decide" - thus, the people doing the work, decide what is done.