I recently installed the update 4.3 to Lightroom running on a Mac under 10.7.5 and lost the exposure controls of the develop module. The develop module now starts with curves. To make changes in light balance, exposure, contrast, light, dark, shadow, highlight, saturation and vibrance I now have to go back to the library module to make changes. This is rather inconvenient. This is happening to photos imported the last couple of days as well as photos imported years earlier.
I have tried resetting Lightroom with no effect. This is seeming more a bug than just some improper setting; at least I have not been able to find anything to change which would restore the develop module to its proper state.
Any ideas how to fix this? Can I get back to an earlier version of Lightroom which works, like 4.2, without making a mess of things? I do not have a camera which needs the latest RAW file readers.