The items in the menu are:
Back button for navigation using the links in Properties entries in the right panel.
Forward button for navigation using the links in Properties entries in the right panel.
Fully expands the packages tree
Collapses the package tree so that only the tree structure is shown
Unmarks all packages
Marks all packages that are members of the selected view
Install the currently selected package
Install all marked packages
Uninstall the currently selected package
Uninstall all marked packages