This menu contains the dialogs you have closed recently. You can reopen a dialog by selecting its name from the list.
This menu contains the list of all dockable dialogs. Select a dockable dialog from the list to change its visibility. If the dialog is opened, it will be closed. If it is closed, then it will be opened.
QChromosome 4D Studio allows opening any number of projects. They are listed at the end of Window menu. To switch between projects just select one of them from the list. Only one project can be edited at a time. Projects appear on the list in the order they were opened.