Every software has bugs. In fact, developers could improve software endlessly. But since the user wants to use the software eventually, it will eventually be distributed even if it is known to contain bugs.
The same is true for CoCoA. Here is a short list of known bugs (I am sure there are more :-):

1. CoCoA freezes while browsing the online manual
   Due to a bug in the HTML renderer in Trolltech's Qt library upon which this user interface is base, the entire application may freeze while you are browsing the online help.
   Specifically, this has been known to occur when you browse the online help, copy something to the clipboard, leave the copied text marked and continue browsing. It has not occured when you copy to the clipboard and then deselect the text. This might be considered as a workaround.
   The bug has been reported to Trolltech and we hope it will be fixed in one of the next releases of the Qt library.
2. WinCoCoA cannot display more than 2048 characters in one line
   This bug may occur when you run WinCoCoA on Windows 95. On these systems, buggy system libraries prevent the display of more that 2048 characters in one line. Therefore, when you set CoCoA to "No WordWrap" and calculate "Fact(1000);" not all digits of the result will be shown. However, you can still copy the digits. So they are there, but you can't see them :-). The only way to fix this is to update Windows or not to use "No WordWrap".
3. Help browser
   • Bookmarks & History
     When you browse the online help and make use of bookmarks you will detect that only the first window of the online help will save its bookmarks and history. This will eventually be resolved.
   • Items not visible
     Sometimes the help browser doesn't determine the size of the window correctly and thus does not display some items. If you suspect there should be more on the page, try to resize the window. It helps most of the time.
   • Quitting CoCoA
     Quitting CoCoA has different effects on different help windows: The first help window you opened will be closed automatically and the application will terminate. If however, you opened other help windows from within the first help window, those will not be closed automatically and the application will not quit. You will have to close them manually. This will be resolved in a future version of CoCoA.
4. Interactive Document
   • Saving
     Currently when you are in the Interactive Document and you select Save as, only the current page of the Interactive Document will be saved. Future versions of CoCoA will probably provide an option to save all pages of the Interactive Document to one file and maybe even a possibility to load such a file into the Interactive Document at startup.
   • Browsing the history
     Currently, there are no keys or menu entries to jump to the first or last history page. This will probably be implemented in a future version of CoCoA.
5. Copying text
   The icon and menu entry for copying text is not active when the output window has the focus. This will be fixed in a future version of CoCoA. For the time being, use the mouse to mark the text you want to copy and press Ctrl + C or use the right mouse button to popup a context menu with edit features or save the whole output window using the Save Output As menu entry.