I am using Lightroom 4.1 RC2 on a Windows 7 64 bit system with dual monitors. When I am in the develop mode and make edit adjustments on any setting the 2nd monitor does not update. If I move to another image then come back the image is updated but it does not work in real time. I have never had this problem before and it worked fine in Lightroom V4.0
It's a bug in LR4.1 RC2.
The workaround seems to be to increase the size of the Standard Preview setting (File Handling tab of the Catalog Settings)....go up at least one setting (e.g. if it's currently 1024 change it to 1440 or 1680). No need to recreate your previews, just increasing the setting seems to work in most cases.
You might also, without realising it, be suffering a fairly dramatic memory leak which is also stopped by changing the settings.
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