I need to suppress items so I can get to things underneath them (because hide doesn't seem to do anything at all). However, while there is a simple right click menu item for suppression, I cannot find any way to unsuppress items. I can't right click on the item as it no longer exist in the side bar, and there doesn't seem to be any menu item anywhere for dealing with suppression. How do I get my stuff back?
Click Settings> Tree Filters from the top of the model tree. From the Model Tree Items dialog box you can then enable Suppressed Objects.
You also might want to take a look at Deleting and Suppressing Items. Hide is used to hide the display of a component and or reference type feature (but it is still in the model). Suppression removes component or feature from the model.