I looked at the issue after trying a few things including:
1. new computer - RMBP
2. new operating system - Lion
3. making a brand new file and brand new layout from FMP 12.
Did it fix the problem? NO. I'm now pretty sure that upgrading to Mountain Lion next month won't fix it either.
The issue seems to be that FMP 12 preview mode has a great deal of problem with a very large field. I have one field, which is 5 pages long. With just over 200 such entries, it takes over 5 minutes for my new RMBP to process things in preview mode. While it calculates, I cannot do anything else with FMP 12.
This really sucks. This was not a problem in FMP 6, 8 or 9. It's a bug that should be fixed.
Do you see any similarities to this known issue? FileMaker 10 Large Text Block Bug
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Phil. I absolutely see similarities. I guess the problem was of disastrous proportions in FMP 10 and was fixed partially in FMP 11 - and still lingering in FMP 12. I'd say that my problem level is 'nuissance' since I don't use preview mode with that particular database very much.
I am quite disturbed after reading your Known Bugs List thread. I flipped through several pages of your thread, and it seems like Bugs do not get fixed in general until a new version comes out. For example, I'm now losing hope that the issue with RMBP http://forums.filemaker.com/posts/17a5af54eb would be resolved before FMP 13 - with 12 having been released only ~3 months ago. Not happy with printing bug either http://forums.filemaker.com/posts/36534c396d ... Sigh. In any case, thanks for pointing out your Known Bugs List thread.
Actually, FileMaker Inc releases free bug fix updates as well as new versions you have to pay for. What they don't do is specifically tell me what bugs were fixed. I and another user (who has a mac) have been slowly working through old bug reports and if we can't reproduce them in 12, we report them as "fixed", but the fix may have been accomplished several releases earlier--we just didn't figure that out until recently--and have many more reports to work through to get things up to date.
The known bugs list is a community supported list of reported bugs. It's only as accurate as the Filemaker community makes it. If you are reading this thread and know of a bug that no longer occurs in your version of FileMaker, let me know so I can update the list.