Why does the BigTime window disappear when I use Digital Cinema Desktop Preview?

If the "Digital Cinema Desktop Preview - Main" mode is used then the BigTime window will disappear. This is the correct behaviour on single monitor systems since Final Cut Pro completely takes over the output to the monitor and all windows on that monitor will be hidden. However on systems with multiple monitors, the BigTime window is hidden even when placed on a monitor not used for DCDP. This appears to be a Final Cut Pro issue since it happens with any application that uses floating windows. We have reported the problem to Apple.

The workaround for systems with multiple monitors is to choose the “Digital Cinema Desktop Preview - Full Screen” mode which uses the secondary monitor and keeps the BigTime window visible.